Ireland has an extensive network of public roads which connect all parts of the country with each other. Roads in Ireland are currently classified as motorways, National Primary routes, National secondary routes, Regional roads and Local roads. The introduction of this classification system began in 1977.
Prior to this, Ireland had a different road classification and numbering system. Roads fell into three categories: T (Trunk Roads), L (Link Roads) and unclassified roads. The origins of this system lie in pre-independence legislation: the preliminary section of Statutory Instrument S.I. No. 55/1926 — Road Signs and Traffic Signals Regulations, 1926states that the Ministry of Transport Act, 1919  gave the Minister for Local Government and Public Health the power to assign a "route letter and number" to a road, while Section 6.4 of Part I of the Regulations specifies the positioning of the "route letter and the number of the road" on directional signs. A reference in the Statutory Instrument to the "classification of roads as a 'Trunk' or 'Link' Road" indicates that a system of route classification and numbering was envisaged in the 1920s. However, at present, there is no information about when the Trunk and Link road-numbering system was actually introduced on signposts. Even though legal authority for the erection of directional signposts was given to local councils, the Automobile Association of Ireland began an extensive road signposting scheme in 1938 which included comprehensive signposting of routes from Belfast, Cork and Dublin.
Evidence that the Trunk Road and Link Road classification and numbering system had been well established by the 1950s is found in Statutory Instrument S.I. No. 284/1956 — Traffic Signs Regulations, 1956which contains examples of several directional signs. The first and second examples show the T8 as the route to Wexford and Rosslare. In addition, Esso road-maps of Ireland from the 1950s show the Trunk and Link road network. Despite its long-standing use, the original Trunk and Link road system was never legislated for and the routes of Trunk Roads and Link Roads were never formally designated by law.
This current system of road classification and numbering has its origins in the late 1960s: the Minister for Local Government, Kevin Boland, announced on 23 July 1969 that a national road network would be formed. In 1974, the Local Government (Roads and Motorways) Act came into effect. It allowed for designation of roads as motorways or national roads. National roads were first designated by Statutory Instrument S.I. No. 164/1977 on 1 June 1977. Twenty-five National Primary routes (N1-N25) and thirty-three National Secondary routes (N51-N83) were initially designated.
The changeover to the new system was gradual: a route planning map of Ireland from the late 1970s (or early 1980s), divided into a northern section and a southern section, shows a mixture of Trunk Road, Link Road and National route numbers.
Major roads were marked with "T" for Trunk Road, less important roads were marked with "L" for Link Road.
Trunk Roads connected major towns to each other while passing through smaller towns and villages.
Several trunk routes were designed to connect towns in different regions of Ireland (for example, the T41 from Enfield to Kilrush, via Tullamore, Portumna, Scariff and Ennis) while other roads (for example, the T66 Ring of Kerry route) were designated scenic routes.
Link Roads connected smaller towns and villages to each other and to the Trunk Road network.
There were eighty-four Trunk Roads in total, numbered from T1 to T77 consecutively (plus T4a, T11a, T12a, T21a, T28a, T50a and T72a). Roads with the 'a' suffix branched off roads with the same number. For example, the T4a branched off the T4 at Ballinasloe in Co. Galway and the T12a branched off the T12 to serve Cobh in Co. Cork.
The first nine Trunk Roads (T1, T2, T3, T4, T4a, T5, T6, T7, T8) radiated out from Dublin (with the T8 branching off the T7 at Enniscorthy) and followed an anti-clockwise pattern. This pattern was similar to the existing anti-clockwise pattern which the National routes and motorways radiating out of Dublin now follow. The pattern was interrupted by the T35 (Dublin-Cavan-Donegal route) which came between the T2 and the T3 and the T42 (now N81), T43 and T44 which came between the T5 (T6) and the T7 routes.
Unlike the present system, where each road (whether N- or R-) has a unique number, under the Trunk and Link Road system, Link Roads were numbered separately beginning with L1. These L (for Link Road) numbers are not related to the current Lxxxx numbers for Local Roads.
Confusingly, some old road signs still show the former (now obsolete) Trunk and Link road-numbers.
Trunk Roads were broadly equivalent to the present National routes, and Link Roads to the present Regional roads. Most of the National Primary and National Secondary routes had been Trunk Roads and generally they followed the routes of these Trunk Roads, albeit with a different numbering system. However, some National Primary and Secondary routes also incorporated Link Roads and unclassified roads into their routes. After the introduction of the new road numbering system, some Trunk Roads (either in whole or in part) were downgraded to Regional roads, effectively 'de-trunked'.
A notable feature of the former system was multiplexing (or concurrency), where a section of road was designated by two or more route numbers. Examples of multiplexes include the T7/T12 multiplex between New Ross and Waterford, the T6/T13 multiplex between Cahir and Kilheffernan (east of Clonmel), the T28/T36 multiplex between Newcastlewest and Abbeyfeale and the short T19/T21 multiplex between Thurles and Toor. The road between Cavan, Butlersbridge, Cloverhill and the border with Northern Ireland (near Wattle Bridge in Co. Fermanagh) was a triple multiplex of the T10, T15 and T35 routes.
Three routes (T15, T22, T35) had sections which were disconnected from the rest of the route by roads which crossed through Northern Ireland. These routes lost their Trunk Road designations through Northern Ireland, regaining them on exiting Northern Ireland. The T15 crossed the border several times between Cavan and Clones, alternating between the T15 and the A3 designations.
Route descriptions show start and end points and selected intermediate destinations and junctions. The current designations of routes (or route sections) is then given.
Multiplex sections (for example, New Ross-Waterford (multiplex with T12)) are shown in italics. Sections of routes through Northern Ireland (with different designations) are shown in bold (for example, border-A37-Cullaville-A37-border or border-(to Belfast via A1)).
|T1||Dublin||(Belfast)||Dublin-Swords-Balbriggan-Drogheda-Dunleer-Dundalk-border-(to Belfast via A1). Now mainly R132 (re-classified, old N1 prior to opening of M1 (Republic of Ireland) and various bypasses).|
|T2||Dublin||(Derry)||Dublin-Ashbourne-Slane-Collon-Ardee-Carrickmacross-Castleblayney-Monaghan-Emyvale-border-(to Derry via A5). Now R135 (sections of former N2 bypassed by HQDC between M50 and Ashbourne and various bypasses) and N2 (Ashbourne-border).|
|T3||Dublin||Sligo||Dublin-Lucan-Leixlip-Maynooth-Enfield-Kinnegad-Mullingar-Edgeworthstown-Longford-Roosky-Dromod-Carrick-on-Shannon-Boyle-Collooney-Sligo. Now N4 (Dublin-Lucan), R148 (sections of former N4 bypassed by M4 and various bypasses) (Lucan-Kinnegad) and N4 (Kinnegad-Sligo).|
|T4||(Dublin)||Galway||(Dublin)-Kinnegad-Rochfortbridge-Kilbeggan-Moate-Athlone-Ballinasloe (multiplex with T31)-Kilconnell-Kiltullagh-Athenry-Derrydonnell-Oranmore-Galway. Now R446 (sections of former N6 bypassed by M6 and various bypasses) (Kinnegad-Athlone), N6 (Athlone-Ballinasloe), R348 (Ballinasloe-Derrydonnell) and old N6 (Derrydonnell-Oranmore-Galway).|
|T4a||Ballinasloe||Loughrea||(Dublin)-Ballinasloe-Garbally-Aughrim-Kilreekill-Kilmeen-Loughrea (multiplex with T21). Now N6 (Ballinasloe-Loughrea), as it was prior to the opening of the Loughrea bypass and other improvements. Multiplexed with T21 from Kilmeen to Loughrea.|
|T5||Dublin||Limerick||Dublin-Naas-Newbridge-Kildare-Monasterevin-Portlaoise-Mountrath-Borris-in-Ossory-Roscrea-Nenagh-Lisnagry-Limerick. Now N7 (Dublin-Naas), R445 (sections of former N7 bypassed by M7 and various bypasses) (Naas-Portlaoise), N7 (Portlaoise-Lisnagry) and R445 (Lisnagry-Limerick).|
|T6||(Dublin)||Cork||(Dublin)-Naas-Kilcullen-Athy-Castlecomer-Henebry's Cross-Kilkenny (multiplex with T14)-Callan-Ninemilehouse-Kilheffernan-Clonmel-Cahir (multiplex with T13)-Kilbehenny-Mitchelstown-Moorepark-Fermoy-Rathcormac-Watergrasshill-Glanmire-Cork. Now R448 (section of N9 bypassed by M9) (Naas-Kilcullen), N78 (Kilcullen-Henebry's Cross), N77 (Henebry's Cross-Kilkenny), N76 (Kilkenny-near Clonmel), old N24 (prior to opening of Clonmel bypass) (nr Clonmel-Cahir), R670 road, R639 (sections of former N8 bypassed by M8 and various bypasses) (Cahir-nr Kilbehenny), N8 (nr Kilbehenny-Moorepark), and R639 (Moorepark-Cork).|
|T7||Dublin||Waterford||Dublin-Stillorgan-nr St. Colmcille's Hospital, Loughlinstown-nr Shankill-Fassaroe-Newtownmountkennedy-Rathnew-Rathdrum-Avoca-Woodenbridge-Arklow-Gorey-Frankfort-Enniscorthy-New Ross-Waterford (multiplex with T12). Now N11 (Dublin-nr St. Colmcille's Hospital, Loughlinstown), Local road (Dublin Rd.) (nr St. Colmcille's Hospital, Loughlinstown-nr Shankill), part of R119 (nr Shankill-Fassaroe), old N11 (Fassaroe-Newtownmountkennedy), R772 (through Newtownmountkennedy), old N11 (Newtownmountkennedy-Rathnew), R752 (Rathnew-Woodenbridge), R747 (Woodenbridge-Arklow), R772 (Arklow-Gorey-Frankfort), N11 (Frankfort-Enniscorthy), N30, ex-N79 (Enniscorthy-New Ross) and N25 (New Ross-Waterford). Note: 'old N11' refers to sections of N11 prior to dualling.|
|T8||Enniscorthy||Rosslare||(Dublin)-Enniscorthy-Oylgate-Ferrycarrig Bridge-Wexford-Blackhorse-Killinick-Rosslare. Now N11 (Enniscorthy-Ferrycarrig Bridge), part of R730 (former sections of N11 & N25 through Wexford prior to opening of Wexford bypass) (Ferrycarrig Bridge-Wexford-Blackhorse) and N25 (Blackhorse-Rosslare).|
|T9||Dundalk||Cahir||Dundalk-Ardee-Kells-Delvin-Mullingar-Kilbeggan-Tullamore-Ballard-Cadamstown-Kinnitty-Boheraphuca-Ballybritt-Roscrea-Templemore-Thurles-Holycross-Cashel-Cahir-(to Cork via T6). Now N52 (Dundalk-Mullingar), Local road (old route of N52 via Ballinagore) (Mullingar-Kilbeggan), N52 (Kilebggan-Tullamore-Ballard), R421 (Ballard-Kinnitty), Local routes via Boheraphuca (Kinnitty-Ballybritt), R421 (Ballybritt-Roscrea), N62 (Roscrea-Thurles), R660 (Thurles-Holycross-Cashel) and R639, old N8 (Cashel-Cahir). Joined T6 to Cork at Cahir.|
|T10||(Enniskillen)||Mullingar||(from Enniskillen)-Wattle Bridge-border-Cloverhill-Butlersbridge-Cavan (multiplex with T35 & T15)-Ballinagh (or Bellananagh)-nr Kilcogy (multiplex with T15)-Finnea-Castlepollard-Mullingar. Started at border nr Wattle Bridge as continuation of A4/A34 route from Enniskillen. Multiplexed with the T35 & T15 from border to Cavan via Butlersbridge. Now N54 (border-Butlersbridge), old N3 (prior to opening of bypasses)(Butlersbridge to Cavan), N55 (Cavan to near Kilcogy), multiplexing with the T15 for this section, and R394 (nr Kilcogy-Mullingar).|
|T11||Cork||(Sligo)||Cork-Mallow-Buttevant-Charleville-Croom-Patrickswell-Limerick-Bunratty-Hurler's Cross-Newmarket on Fergus-Ennis-Crusheen-Gort-Coole-Lydican-Drumharsna-Owenbristy-Kiltiernan-Kilcolgan-Clarinbridge-Oranmore-Galway (multiplex with T4)-Claregalway-Tuam-Dunmore-Cloonfad-Ballyhaunis-Tawnyinah-Charlestown-Tubbercurry-Collooney-joined T3 to Sligo. Main route along western side of Ireland from Cork to Sligo via Limerick and Galway. Followed various pre-improvement National and Local routes: Cork-Limerick (N20), Limerick-Coole (north of Gort) (N18), Coole-Kiltiernan (current Local roads), Kiltiernan-Oranmore (N18), Oranmore-Galway (N6), Galway-Tuam (N17), Tuam-near Tavraun (approx. 14 km/8.75 miles north of Ballyhaunis) (N83), Tavraun-Lurga Lower (approx. 5 km/3miles south of Charlestown) via Tawnyinah (current Local roads), Lurga Lower-Charlestown-Collooney (N17), joined T3 to Sligo at Collooney.|
|T11a||Dunmore||Ballymoe||Dunmore-Williamstown-Ballymoe. Followed route of current R360 from Dunmore to Ballymoe, connected T11 to T39 (now N60).|
|T12||Cork||Wexford||Cork-Dunkettle-Carrigtwohill-Midleton-Castlemartyr-Killeagh-Youghal-Dungarvan-Joulterspark-Lemybrien-Kilmeaden-Waterford-New Ross (multiplex with T7)-Wexford. Followed route of pre-improvement N25 from Cork to Wexford. Multiplexed with T7 from Waterford to New Ross.|
|T12a||(Cork)||Cobh||(Cork)-Cobh Cross-Cobh. Followed route of current R624, connecting Cobh with the T12 (now N25) at Cobh Cross.|
|T13||Limerick||Waterford||Limerick-Tipperary-Bansha-Cahir-Clonmel-Kilheffernan (multiplex with T6)-Carrick on Suir-Mooncoin-Waterford. Followed route of pre-improvement N24 between Limerick and Waterford. Multiplexed with T6 between Cahir and Kilheffernan (east of Clonmel, at the current junction of the N24 and the N76).|
|T14||Waterford||Tullamore||Waterford-Mullinavat-Ballyhale-Knocktopher-Stoneyford-Kilkenny-Henebry's Cross (multiplex with T6)-Ballyragget-Ballinakill-Abbeyleix-Portlaoise-Mountmellick-Tullamore. Followed various pre-improvement National and Regional routes: Waterford-nr Ballyhale (current N9/southern N10 junction) (N9), nr Ballyhale-Kilkenny (southern N10), Kilkenny-Henebry's Cross (junction of the N77 and N78, multiplex with T6)-Ballyragget (N77), Ballyragget-nr Abbeyleix (R432), nr Abbeyleix-centre of Abbeyleix (R340 Ballinakill Road), Abbeyleix-Portlaoise (N8), Portlaoise-Mountmellick-Tullamore (N80).|
|T15||(Galway)||(Monaghan)||(Galway)-Roouanmore-Lackagh-Turloughmore-Moylough-Mountbellew-Athleague-Roscommon-Lanesborough-Longford-Ballinalee-Granard-nr Kilcogy-Ballinagh (or Bellananagh)-Cavan (multiplex with T10)-Butlersbridge-Leggykelly (multiplex with T10-T35)-border-A3-Co. Fermanagh-border-re-entered Co. Cavan-T15-border (Derrynure)-A3-Co. Fermanagh-border-entered Co. Monaghan-T15-Clones-Smithborough-Monaghan Town-border (Tamlat)-(to Armagh via A3). Roounamore (near Lackagh, junction of T11 & T15, now junction of N17 & N63)-Roscommon-Longford (N63), Longford-Granard (section of R194), Granard-Cavan (N55), Cavan-Butler's Bridge (N3), Butler's Bridge-Clones-Monaghan (N54,A3: crossing border several times), Monaghan-border (N12), joined A3 to Armagh & Belfast.|
|T16||(Enniscorthy)||Portlaoise||(Enniscorthy)-Ballynahallin-Bunclody-Ballon-Carlow-Ballickmoyler-Arless-Stradbally-Portlaoise. Followed route of southern part of N80 from Ballynahallin (current junction of N11 & N80, then junction of T16 & T7) nr Enniscorthy-Carlow-Portlaoise.|
|T17||Sligo||(Enniskillen)||Sligo-Manorhamilton-Blacklion-border-(to Enniskillen and Belfast via A4 and, later, NI's M1). Sligo-border at Blacklion (N16), joined A4 to Enniskillen & Belfast.|
|T18||Sligo||(Derry)||Sligo-Grange-Drumcliffe-Bundoran-Ballyshannon-Donegal-Ballybofey-Stranorlar-Killygordon-Castlefin-Cloghfin-border-Clady-(to Strabane and Derry via B85-A5). Followed N15 (as it was prior to the Ballyshannon/Bundoran and Donegal bypasses) from Sligo to Cloghfin near the border, continued across border to Clady, Co. Tyrone, then from Clady to Strabane (B85), joined A5 to Derry.|
|T19||Kilkenny||(Limerick)||Kilkenny-Freshford-Urlingford-Turnpike (multiplex with T36)-Thurles-Toor (multiplex with T21)-Ballycahill-Rosmult-Milestone-Inch-Anglesey Bridge-Rear Cros-Newport-Lisnagry-(to Limerick via T5). Followed various National and Regional routes: Kilkenny to Urlingford (R693), multiplexed with T36 (part of the old N8, now R639) from Urlingford to Turnpike (junction of old N8 and N75), Turnpike-Thurles (N75), Thurles-Toor (now junction of R498 and R503) via R498, Toor-Lisnagry (R503), joined T5 (old N7, now R445) to Limerick.|
|T20||Kilkenny||New Ross||Kilkenny-Bennettsbridge-Thomastown-Inistioge-New Ross. Connected Kilkenny with New Ross via Thomastown, following the route of the R700.|
|T21||Thurles||(Galway)||Thurles-Toor (multiplex with T19)-Borrisoleigh-Nenagh-Borrisokane-Portumna-Killimor-Ballydavid-Killmeen-Loughrea (mulitplex with T4a)-Craughwell-Derrydonnell (to Galway via T4). Thurles-Nenagh (R498), Nenagh-Portumna-Loughrea (N65), Loughrea-Derrydonnell (route of pre-Loughrea bypass N6), joined T4 to Galway.|
|T21a||Borrisokane||Moneygall||Borrisokane-Cloughjordan-Moneygall. Connected T21 (now part of N65) & T33 (now part of N52) at Borrisokane to T5 (now N7) at Moneygall, following current R490 route via Cloughjordan.|
|T22||Dundalk||Castleblayney||Dundalk-border-A37-Cullaville-A37-border-re-entered Co. Monaghan-T22-Castleblayney. Dundalk-Castleblayney, via Cullaville in Northern Ireland as A37. Now N53/A37.|
|T23||Dundalk||(Armagh)||Dundalk-Kilcurry-border-(to Newtownhamilton, Keady and Armagh via A29). Dundalk-border via Kilcurry, following R177 route, joined A29 to Armagh.|
|T24||Dundalk||Granard||Dundalk-Chanonrock-Carrickmacross-Corvally-Shercock-Bailieborough-Virginia-Ballyjamesduff-Ballymachugh-nr Finnea-Granard. Dundalk-Virginia (R178), Virginia-Granard (R194), joined T31 & T15) at Granard.|
|T25||(Drogheda)||Collon||(Drogheda)-Collon. Branched off T1 (via part of the T26, now N51) nr Drogheda, went to Collon. Connected T1 & T2. Followed current R168 route.|
|T26||Drogheda||Kinnegad||Drogheda-Slane-Navan-Bective Abbey-Trim-Kinnegad. Drogheda-Slane-Navan (N51), Navan-Trim-Kinnegad (R161), joined T3 & T4 at Kinnegad.|
|T27||(Youghal)||Clonmel||(Youghal)-Kinsalebeg-Clashmore-Modeligo-Halfwayhouse Inn-Ballymacarbry-Clonmel. Connected T12 (now N25) at Kinsalebeg, nr Youghal, with Clonmel. Followed current R671.|
|T28||(Limerick)||Tralee||(Limerick)-Patrickswell-Adare-Rathkeale-Newcastlewest-Abbeyfeale (multiplex with T36)-Castleisland-Caherbreagh-Tralee. Now N21 (as it was prior to opening of vavPatrickswell and Tralee.|
|T28a||Castleisland||Farranfore||Castleisland-Farranfore. Now N23.|
|T29||(Tralee)||Cork||(Tralee)-Caherbreagh-Farranfore-Killarney-Ballyvourney-Macroom-Coachford-Carrigrohane-Cork. Caherbreagh (junction with the T28, now junction of the N21 & N22)-Killarney-Macroom (pre-improvement N22), Macroom-Coachford-Carrigrohane (R618), then Carrigrohane Road to Cork.|
|T30||(Dungarvan)||(Killarney)||(Dungarvan)-Joulterspark-Cappoquin-nr Lismore-Ballyduff-Fermoy-Castletownroche-Mallow-Rathmore-Clasheen-(to Killarney via T29). Now part of N72 (Joulterspark-nr Lismore), R666 (nr Lismore-Fermoy) and part of N72 (Fermoy-Clasheen). Joined T29 (now N22) to Killarney.|
|T31||Portumna||Granard||Portumna-Ballinasloe-Athlone (multiplex with T4)-Ballymahon-Edgeworthstown-Granard. Now R355 (Portumna-Ballinasloe), part of N6 (Ballinasloe-Athlone) and part of N55 (Athlone-Granard).|
|T32||Roscrea||(Athlone)||Roscrea-Birr-Cloghan-Ferbane-Fardrum-(to Athlone via T4). Now part of N62.|
|T33||Birr||Borrisokane||Birr-Ballingarry-Borrisokane. Now part of N52.|
|T34||Athlone||Boyle||Athlone-Roscommon-Tulsk-Boyle. Now N61.|
|T35||Dublin||(Donegal)||Dublin-Clonee-Dunshaughlin-Navan-Kells-Virginia-Cavan-Butlersbridge-Cloverhill-border-(multiplex with T10-T15)-A3-Wattle Bridge-A34-Newtownbutler-Lisnaskea-Tamlaght-A4-Enniskillen-A32-Irvinestown-A35-Kesh-border-T35-Pettigo-Laghey-(to Donegal via T18). Now N3 (Dublin-Butlersbridge), N54 (Butlersbridge-border nr Wattle Bridge), A3-B533 (Wattle Bridge-Netwownbutler)-A34 (Newtownbutler-Lisniskea)-B514 (Lisnaskea-Tamlaght)-A4-A32-A35, R232 (Pettigo-Laghey), N15 (ex-T18).|
|T36||Abbeyleix||Listowel||Abbeyleix-Durrow-Cullahill-Urlingford-Turnpike (multiplex with T19)-Horse and Jockey-Cashel-Golden-Tipperary-Emly-Kilmallock-Charleville-Drumcolliher-Feohanagh-Newcastlewest-Abbeyfeale (multiplex with T28)-Duagh-Listowel. Now part of R639 (old N8) (Cullahill-Cashel), N74 (Cashel-Tipperary), R515 (Tipperary-Drumcolliher), R522 (Dromcolliher-Newcastlewest), N21 (Newcastlewest-Abbeyfeale), R555 (Abbeyfeale-Listowel).|
|T37||Cashel||(Kilkenny)||Cashel-Dually-Ballinure-Laffansbridge-Killenaule-Ballingarry-Ballyline-Ballymack-(to Kilkenny via T6). Now R691.|
|T38||Mitchelstown||Mallow||Mitchelstown-Kildorrery-Mallow. Now N73.|
|T39||Roscommon||Louisburgh||Roscommon-Ballymoe-Castlerea-Ballyhaunis-Claremorris-Balla-Castlebar-Westport-Louisburgh. Now N60 (Roscommon-Castlebar), N5 (Castlebar-Westport) and part of R335 (Westport-Louisburgh).|
|T40||(Sligo)||Galway||(Sligo)-Ballysodare-Beltra-Dromore West-Easky-Rathlee-Kilglass-Enniscrone-Corraun-Ballina-Foxford-Strade-Bellavary-Castlebar-Ballintubber-Partry-Ballinrobe-Kilmaine-Shrule-Headford-Galway. Now part of N59 (Ballysodare-Dromore West), R297 (Dromore West-Carraun), re-joins N59 (Corraun-Ballina), part of N26, ex-N57 (Ballina-Foxford), N58 (Foxford-Bellavary), N5 (Bellavary-Castlebar) and N84 (Castlebar-Galway).|
|T41||Enfield||Kilrush||(Dublin)-Enfield-Edenderry-Daingean-Ballinagar-Clonmore-Cappincur-Tullamore-Screggan-Blue Ball-Kilcormac-Birr-Riverstown-Pike-Portland-Portumna-Power's Cross-Gorteeny-Mountshannon-Scariff-Tuamgraney-Bodyke-Moymore-Spancil Hill-Ennis-Darragh-Caherea-Lissycasey-Knockalough-Kilrush. Now part of R402 (Enfield-Ballinagar), Local road (Ballinagar-Clonmore-Cappincur-Tullamore), part of N52 (Tullamore-Riverstown), R489 (Riverstown-Portland), part of N65 (Portland-Portumna) and R352 (Portumna-Ennis) and N68 (Ennis-Kilrush).|
|T42||Dublin||Clash||Dublin-Templeogue-Tallaght-Brittas-Blessington-Baltinglass-Rathvilly-Tullow-Clash-(joined T16). Now N81.|
|T43||Dublin||(Bray)||Dublin-Milltown-Windy Arbour-Dundrum-Sandyford-Stepaside-Kiltiernan-Enniskerry-Fassaroe-(Bray). Now R117.|
|T44||Dublin||(Shankill)||Dublin-Ballsbridge-Merrion-Booterstown-Blackrock-Monkstown-Dun Laoghaire-Dalkey-Killiney-(Shankill)-(to Bray via T7). Now part of R118 (Lwr. Mount St.-Northumberland Rd.-Pembroke Rd.- Merrion Rd.- Rock Rd.-Blackrock), part of N31 (Blackrock-Frascati Rd.-Dun Laoghaire) and part of R119 (Dun Laoghaire-Marine Drive-Upr. Georges St.-Summerhill Rd.-Glasthule Rd.-Sandycove Rd.-Breffni Rd.-Ulverton Rd.-Dalkey-Castle St.-Sorrento Rd.-Vico Rd.-Station Rd.-Killiney-Seafield Rd.-Killiney Hill Rd.-Shanganagh Rd.-(joined Dublin Rd., former T7)-(to Shankill & Bray via T7).|
|T45||Clones||(Newry)||Clones-Killeevan-Newbliss-Ballybay-Castleblayney-Milltown-border-(to Newtownhamilton & Newry via A25). Now R183 (Clones-Castleblayney) andR182 (Castleblayney to border).|
|T46||Carrickmacross||Ballybay||Carrickmacross-Ballybay. Now R180.|
|T47||Tullamore||(Athlone)||Tullamore-Clara-Moate-(to Athlone via T4). Now part of N80.|
|T48||Durrow||(Borris-in-Ossory)||Durrow-Ballycolla-Aghaboe-Sentry Hill-(to Borris in Ossory and Roscrea via T5). Now R434.|
|T49||Cashel||Clonmel||Cashel-Rosegreen-Ballyclerahan-Clonmel. Now R688.|
|T50||Mitchelstown||(Limerick)||Mitchelstown-Ballylanders-Knocklong-Hospital-Newline (multiplexed with T57)-Caherconlish-Beary's Cross-(to Limerick via T13). Now R513.|
|T50a||Kilmallock||(Limerick)||Kilmallock-Bruff-Holy Cross-nr Ballybricken-(to Limerick via T57). Now part of R512.|
|T51||Kilcullen||Kilkenny||(Dublin & Naas)-Kilcullen-Timolin-Moone-Castledermot-Carlow-Leighlinbridge-Paulstown-Kilkenny. Now N9 (Kilcullen-Paulstown) and N10 from (Paulstown-Kilkenny).|
|T52||(Drumsna)||Belturbet||(Drumsna)-Annaduff-Mohill-Cloone Grange-Carrigallen-Killeshandra-Milltown Abbey-Lisnamaine-Kilconney-Belturbet-Sugarloaf-Gannons Cross-joined T10-T35 multiplex. Now R201 (Annaduff-Lisnamaine), N87, former R200 (Lisnamaine-Kilconney), N3 (Kilconney-Belturbet-Sugarloaf) and R197 (Sugarloaf to Gannons Cross).|
|T53||Dromod||Swanlinbar||Dromod-Mohill-Garvagh-Fenagh-Ballinamore-Gortmore-Swanlinbar-border-(to Enniskillen via A32-A4). Now R202 (Dromod to Gortmore) and N87, former R200 (Gortmore to border). Joined A32 at border (to Enniskillen).|
|T54||Carrick on Shannon||Bundoran||Carrick on Shannon-Leitrim-Drumgorman-Drumshanbo-Tarmon-Drumkeeran-Killarga-Manorhamilton-Glenade-Kinlough-Bundoran. Now R280 (Carrick on Shannon-Drumgorman), R207 (Drumgorman-Drumshanbo), R208 (through Drumshanbo: Chruch Street-bridge over River Shannon), R280 (bridge-Bundoran).|
|T55||(Carrick on Shannon)||Fenagh||(Carrick on Shannon)-Drumheckil-Keshcarrigan-Fenagh-joined T53. Now R209.|
|T56||Carrick on Suir||(Kilkenny)||Carrick on Suir-Ballinacluna-(Kilkenny via T6). Now R696.|
|T57||Limerick||Emly||Limerick-Ballyneety-nr Ballybricken-Mohane-Newline-Hospital (multiplexed with T50)-Emly (joined T36). Limerick-nr Ballybricken (R512), nr Ballybricken-Mohane (R514), Mohane-Hospital (R513), Hospital-Emly (R516).|
|T58||Ballina||Belmullet||Ballina-Crossmolina-Bellacorick-Bangor Erris-Bunnahowen-Belmullet. Now N59 (Ballina-Bangor Erris) and R313 (Bangor Erris-Belmullet).|
|T59||Stranorlar||(Derry)||Stranorlar-Kilross-Letterkenny-Manorcunningham-Newtown Cunningham-Speenoge-Bridge End-border-(to Derry via A2). Now N13. Stranorlar to Letterkenny was originally classified as a National Secondary route (part of the N56) when the national road numbering system was implemented. However, it was upgraded to National Primary route status in the 1990s as a southern extension to the N13.|
|T60||(Letterkenny)||Lifford||(Letterkenny)-nr Corkey-Lifford-border-A38-Strabane-(to Derry & Dublin via A5). Now N14, became A38 at border to junction with A5.|
|T61||(Bray)||Rathdrum||(Bray)-Kilmacanogue-Killough-Roundwood-Annamoe-Laragh-Rathdrum. Now R755.|
|T62||(Dundalk)||(Omeath)||(Dundalk)-Ballymascanlan-The Bush-Carlingford-Omeath-Cornamucklagh-border-(to Newry via B79). Now R173 (Cooley Peninsula drive).|
|T63||Waterford||Dungarvan||Waterford-Tramore-Annestown-Knockmahon-Bunmahon-Stradbally-Dungarvan. Now R675 (Waterford-Bunmahon), Local routes (bunmahon-Ballyvoile) and rejoins R675 (Ballyvoile-Dungarvan).|
|T64||Macroom||(Bantry)||Macroom-Kilbarry-Inchigeelagh-Ballingeary-Kealkill-Ballylickey-(to Bantry via T65). Now R584 (Macroom-Ballylickey).|
|T65||Killarney||Cork||Killarney-Kenmare-Glengarriff-Bantry-Scart-Aghaville-Drimoleague-Dunmanway-Enniskeane-Bandon-Inishannon-Halfway-Cork. Now N71 (Killarney-Scart), R586 (Scart-Bandon), rejoined old N71 (as it was prior to improvements between Cork and Inishannon, including Halfway bypass) (Bandon-Cork).|
|T66||Tralee||Kenmare||Tralee-Castlemaine-Killorglin-Glenbeigh-Cahirciveen-Waterville-Caherdaniel-Sneem-Parknasilla-Kenmare (part of Ring of Kerry route). Now N70 (part of Ring of Kerry route).|
|T67||Killorglin||Killarney||Killorglin-Killarney (part of Ring of Kerry route). Now part of N72 (part of Ring of Kerry route).|
|T68||Limerick||Dingle||Limerick-Kildimo-Askeaton-Foynes-Tarbert-Listowel-Tralee-Camp-Annascaul-Dingle. Now N69 (Limerick-Listowel-Tralee) and N86 (Tralee-Dingle).|
|T69||Kilcolgan||Kilrush||Kilcolgan-Kinvara-Ballyvaughan-Lisdoonvarna-Ennistymon-Lahinch-Miltown Malbay-Quilty-Doonbeg-Kilkee-Kilrush. Now N67.|
|T70||Ennistymon||Ennis||Ennistymon-Ennis. Now N85 (was Regional route until 1990s).|
|T71||Galway||Bangor Erris||Galway-Moycullen-Oughterard-Maam Cross-Recess-Clifden-Letterfrack-Kylemore Abbey-Leenane-Carrowkennedy-Liscarney-Westport-Newport-Mulrany-Ballycroy-Bangor Erris. Now part of the N59.|
|T72||Donegal||Letterkenny||Donegal-Inver-Dunkineely-Five Points-Ardara-Kilrean-Glenties-Lettermacaward-Dungloe-Burtonport-Kincasslagh-Crolly-Dore-Bunbeg-Brinlack-Gortahork-Falcarragh-Dunfanaghy-Creeslough-Cashel-Carrigart-Milford-Ramelton-Letterkenny (West Donegal Coastal Route). Large parts of this route were identical to the N56 (West Donegal Coastal Route), but the T72 diverged from the exisiting N56 between Dungloe and Crolly (via Burtonport and Kincasslagh) following the route of the R259. The next divergence was from near Dore to Gortahork via Bunbeg and Brinlack with the T72 following the route of the R257. The T72 followed a very different route from Creeslough to Letterkenny compared to the N56. Just south of Creeslough, the T72 turned north-east to Carrigart via Cashel. From Carrigart it went south towards Letterkenny via Milford and Ramelton. The section of the T72 between Creeslough and Letterkeeny is now the R245.|
|T72a||Donegal||Malin More||(Donegal)-Five Points-Killybegs-Kilcar-Glencolumbkille-Malin More. Now part of R263.|
|T73||Speenoge||(Derry)||Inishowen Ring: Speenoge-Burnfoot-Fahan-Buncrana-Drumfree-Clonmany-Ballyliffen-Carndonagh-Gleneely-Moville-Whitecastle-Quigley’s Point-Muff-border (Culmore)-(to Derry via A2). The route of the T73 was almost identical to the route of the R238 (Inishowen Ring), except for the section between Carndonagh and Gleneely which did not follow the line of the present route of the R238 from Carndonagh to Culdaff to Gleneely. Instead the T73 went directly between Carndonagh and Gleneely following the line of a current Local route.|
|T74||Letterkenny||(Derry)||(Letterkenny)-Newtown Cunningham-Speenoge-Bridge End-border-(to Derry via A2). Now part of the N13, A2 from border.|
|T75||(Dungarvan)||(Clonmel)||(Dungarvan)-Ballymacmague South-Halfway House Inn-(to Clonmel via T27). Now part of the R672.|
|T76||Borrisoleigh||Templemore||Borrisoleigh-Templemore. Now the R501.|
|T77||Longford||Foxford||Longord-Strokestown-Tulsk-Frenchpark-Ballaghaderreen-Charlestown-Swinford-Foxford. Longford to Swinford is now part of the N5, Swinford to Foxford is now part of the N26.|