Interstate 15 in California: Wikis


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Interstate 15 shield
Interstate 15
Main route of the Interstate Highway System
Defined by S&HC § 315, maintained by Caltrans
Length: 287.26 mi[1] (462.30 km)
Formed: 1957
South end: I-8 / SR 15 in San Diego
SR 78 in Escondido
I-215 in Murrieta
I-10 in Ontario
I-215 in San Bernardino
SR 18 in Victorville
I-40 in Barstow
North end: I-15 in Primm, Nevada
State highways in California (list - pre-1964)
< SR 14 SR 15 >
History - Unconstructed - Deleted - Freeway - Scenic

In the U.S. state of California, Interstate 15 (I-15) is a major north–south route through the San Bernardino, Riverside, and San Diego Counties, and it has a length of 287.26 miles (462 km) in the state. It is a major thoroughfare for traffic between Southern California, Las Vegas, Nevada, and points beyond. The Cronese Mountains are found north of it. It is also the main route for traffic between San Diego and the Inland Empire.

This route is part of the California Freeway and Expressway System[2] and it is eligible for the State Scenic Highway System.[3]


Route description

Interstate 15's southern terminus is presently at Interstate 8 in San Diego. From I-8, it runs north through Escondido in San Diego County, passing the Marine Corps Air Station Miramar. The Interstate Highway passes through hilly terrain and farmland before entering Riverside County near the rapidly-growing community of Temecula, California.

In Murrieta, I-15 splits from its first (and only) spur route in California, Interstate 215, which runs through the two largest cities in the Inland Empire: San Bernardino and Riverside. I-15 runs along the eastern edge of the Santa Ana Mountains, passing the town of Lake Elsinore. The freeway continues through the suburban areas in the western Inland Empire, passing Corona and Ontario. The highway is then rejoined by I-215 before heading northwards and upward through the Cajon Pass, the important mountain pass that serves as the primary route between Southern California points eastwards and northeastwards.

The portion of I-15 that is located between its northern and southern junctions with I-215 is also used by many local residents as the major north–south route for the western portions of the San Bernardino-Riverside-Ontario metropolitan area. (I-215 serves a similar function in the eastern portion of the metropolitan area. These two highways are the only continuous north–south freeways in the area.)

North of the Cajon Pass, I-15 traverses the Mojave Desert towns of Hesperia and Victorville. I-15 passes through mostly unspoiled desert for 30 miles (48 km) before reaching Barstow, California, the last town that I-15 passes through in California. The only other settlement I-15 passes through in its final 108 miles (174 km) is Baker, California. The sign for the Zzyzx exit, the alphabetically last place name in the United States, is a somewhat-known landmark along the drive from Los Angeles to Las Vegas, Nevada on I-15. I-15 leaves California near the casino town of Primm, Nevada (formerly known as Stateline, Nevada).

Escondido Freeway

Heading northward, I-15 currently begins at Interstate 8 at the same place that its continuation, State Route 15, begins its southward journey. I-15 goes through Mission Valley and intersects with State Route 52 and merges with State Route 163. After traversing the Marine Corps Air Station Miramar, I-15 emerges into Carmel Valley, where it intersects with the end of State Route 56. I-15 continues north into Escondido, where it interchanges with State Route 78. North of Escondido, I-15 goes through rural areas, intersecting State Route 76 before it crosses the county line into Riverside County. In Riverside County, SR 79 runs concurrently with I-15 for a four-mile (6 km) portion within the city of Temecula before it splits away to continue north to Hemet. Then, I-15 intersects with the southern end of Interstate 215, which carries the designation of the "Escondido Freeway". Interstate-15 continues north as the Temecula Valley Freeway.[4]

On January 24, 1957, the State Highway Commission defined the Escondido Freeway as what are now Routes 15 and 215 from Route 805 to Route 91. Note that this entire segment was previously U.S. Route-395 when it was named. Since then, the definition was extended on Route 15 south to Route 8 by Assembly Concurrent Resolution 34, Chapter 67 in 1979.[5] Meanwhile, the segment of Route 15 from the San Diego County Line to the I-15/I-215 interchange was named the Temecula Valley Freeway in 1990.[6]

I-15 between SR 163 and Pomerado Road/Miramar Road is also known as the Semper Fi Highway in recognition of the nearby Marine Corps Air Station Miramar.[7]

There are high-occupancy toll lanes in the center of I-15 from State Route 163 to State Route 56.[8] Construction is currently ongoing (as of spring 2008) to extend these lanes northward to SR 78. The current HOT lanes from SR 163 to SR 56 are being expanded to four lanes as part of the same project.

I-15 north of the Escondido city limits is also known as the Avocado Highway, whose designation ends upon entering Temecula.

Temecula Valley Freeway

The Temecula Valley Freeway is a segment of Interstate 15 in Riverside County, California, United States, traveling southeast to northwest through the southern portions of the Inland Empire region. It begins at the Riverside/San Diego county line, travels north through the cities of Temecula and Murrieta (where the Escondido Freeway designation switches to Interstate 215), and ends at Bundy Canyon Road near Lake Elsinore. Thereafter, I-15 is designated as the Corona Freeway.

Corona Freeway

The Corona Freeway is a freeway traveling through Riverside County, California. It is signed as Interstate 15 along its entire length. The Corona Freeway runs north–south from its southern terminus at I-215 near Temecula to its northern terminus at the Riverside Freeway (State Route 91).

The original definition for the Corona Freeway, as named by the State Highway Commission on July 23, 1958, stated that it was "Routes 71, 91, and 15 from Route 10 West of Pomona to Route 215".[9]

This legal definition has been amended twice: First in 1990, the California Assembly passed Concurrent Resolution 125, Chapter 78, renaming I-15 between the San Diego County Line (which is further south from Interstate 215) and Bundy Canyon Road near Lake Elsinore as the Temecula Valley Freeway.[10]

Then in 1993, the California Assembly passed legislation officially designating State Route 71 as a part of the Chino Valley Freeway.[11] However, the name "Corona Freeway" is, confusingly, sometimes still applied to this portion of State Route 71; despite the change, guide signs on I-10 eastbound and SR 57 southbound at the Kellogg Interchange in Pomona still refer to SR 71 as the "Corona Freeway".

Ontario Freeway

The Ontario Freeway (formerly known as the Devore Freeway) is a segment of Interstate 15 in southern California, running through San Bernardino and Riverside counties. It is the principal north–south freeway through the fast-growing Inland Empire region.

North of Limonite Avenue (south of SR 60), I-15 is known as the Ontario Freeway. I-15 intersects State Route 60, Interstate 10, and Interstate 210 in rapid succession as it goes through Norco and Rancho Cucamonga. As it nears Devore, I-15 merges with Interstate 215 and becomes what is known as the Barstow Freeway or the Mojave Freeway.

Mojave Freeway

West of Baker, the freeway jogs to pass north of Cave Mountain.

The Mojave Freeway is the name given to the segment of Interstate 15 in California between the northern I-215 junction and the Nevada state line. The portion between former State Route 30 and the Nevada state line is also known as the Barstow Freeway. It is the principal route between Los Angeles, Las Vegas, Nevada, and points to the north and east.

Westbound coming down into Shadow Valley; Halloran Summit is on the skyline, about 8 miles (13 km) away.

The Ontario (I-15) and Barstow (I-215) freeways meet in Devore, a foothill town just northwest of San Bernardino, merging into the Mojave Freeway. Crossing the San Bernardino Mountains at the Cajon Pass, the freeway enters the Victor Valley and continues northeast through the Mojave Desert. It terminates at the Nevada state line; I-15 continues thereafter to Las Vegas, Salt Lake City, and on into Idaho and Montana, before ending at the Canadan border. Because it joins with the western end of I-70 in Southwestern Utah, I-15 also forms part of a major east–west corridor connecting Southern California with Denver, St. Louis, and points east.

The Mojave Freeway is fairly busy on weekdays, since it connects the rapidly growing exurbs of the Victor Valley with the Los Angeles area. On weekends and holidays, however, it can sometimes be largely jammed with Californians driving to Las Vegas for short vacations.

Construction is currently underway to rehabilitate the pavement on I-15 and to add truck lanes to speed up auto traffic by separating autos from trucks.


I-15 replaced US 395 between San Diego and Temecula. The highway replaced US 66 between San Bernardino and Barstow. The route north of Barstow replaced US 91.

I-15 was initially planned to run from I-10 in San Bernardino along the current I-215 alignment then up through the Cajon Pass and on to Las Vegas, with a distance of 186.24 miles (299.72 km) within the state. California successfully argued the addition south to San Diego, suggesting that the freeway would connect the major military bases former March AFB and former NAS (now MCAS) Miramar. US 395 was then signed TEMP-15 and the "old" I-15 between Devore and San Bernardino became I-215.

State Route 31

In 1933, Interstate 15 was defined as Legislative Route 193, running from pre-1964 Legislative Route 43 (present State Route 91) in Corona to pre-1964 Legislative Route 9 (now State Route 66, and was extended north to pre-1964 Legislative Route 31 (present I-15 and I-215) in 1935.[12] The piece south of U.S. Route 60 (Mission Boulevard), running along North Main Street, Hamner Avenue and Milliken Avenue, was state-maintained by 1955, but was not assigned a signed number.[13] This was still the only existing piece in 1963, and had a planned freeway replacement to the east.[14]

In the 1964 renumbering, the route was assigned as State Route 31. It was added to the Interstate Highway System in February 1972 as a realignment of Interstate 15 (the former alignment became Interstate 15E).[15] Legislative changes were made in 1974, eliminating SR 31 (along with State Route 71 south of Corona) in favor of I-15.[16] However, SR 31 continued to be signed — as TEMPORARY Interstate 15 - until present I-15 was finished. (A 1986 map shows state maintenance continuing north past SR 60 to Jurupa Street, where it turned east to I-15.[17])


California State Route 15 from Interstate 5 to Interstate 8 in San Diego will be re-designated as part of I-15 once this segment is completely upgraded to Interstate standards.

Most of Interstate 15 is undergoing major improvements from Devore to the Nevada State Line, beginning in 2002 and costing $349 million. This project will improve traffic flow on the heavily traveled highway for those going to and from Las Vegas. Most of the construction will be completed by Winter 2009.[18] Projects include adding truck lanes on hills (39 miles at various locations), repaving 76 miles (122 km) of I-15 at various locations, adding exit numbers, renovating and rehabilitating the rest area between Baker and the Nevada State Line (Valley Wells Rest Area), reconstructing bridges in Baker, and moving the agriculture inspection station from Yermo to the Nevada State Line and including a truck weigh station.

As of March 2008, construction is underway to add a northbound truck descending lane and to repave lanes between Bailey Rd. and Yates Well Rd.

There is also construction ongoing (circa spring 2008) to expand traffic lanes in northern San Diego County, including the northward extension (beyond SR 56) of the existing high-occupancy toll lanes which already exist between SR 56 and SR 163. It appears that this extension will move the northern terminus of the HOT lanes to a location at or near the interchange with SR 78.

Exit list

Note: Except where prefixed with a letter, postmiles were measured in 1964, based on the alignment as it existed at that time, and do not necessarily reflect current mileage. The numbers reset at county lines; the start and end postmiles in each county are given in the county column.
County Location Postmile
#[22] Destinations Notes
San Diego
SD R6.13-R54.26
San Diego R6.13 SR 15 south (Escondido Freeway) – San Diego Continuation beyond I-8
6B Camino del Rio South
R6.13 6B I-8El Centro, Beaches
R6.82 7 Friars Road – Qualcomm Stadium Signed as exits 7A (east) and 7B (west) northbound
R8.37 8 Aero Drive
R9.24 9 Balboa Avenue, Tierrasanta Boulevard Former SR 274 west
R10.00 10 Clairemont Mesa Boulevard Southbound exit is part of exit 11
R10.58 11 SR 52
M12.12 12 SR 163 south (Cabrillo Freeway) Northbound exit is via exit 11; former US 395 south
M13.33 13 Miramar Way Serves Marine Corps Air Station Miramar
M14.29 14 Miramar Road, Pomerado Road
M15.00 15 Carroll Canyon Road
M15.92 16 Mira Mesa Boulevard
M17.31 17 Mercy Road, Scripps Poway Parkway
M18.18 18 Poway Road (CR S4), Rancho Peñasquitos Boulevard
M19.47 19 SR 56 west (Ted Williams Freeway) / Ted Williams Parkway
M20.57 21 Carmel Mountain Road
M21.92 22 Camino del Norte
M22.94 23 Bernardo Center Drive
M23.69 24 Rancho Bernardo Road
M26.03 26 Pomerado Road (CR S5), West Bernardo Drive
Escondido M26.97 27 Via Rancho Parkway
M27.65 28 Centre City Parkway (I-15 Bus. north) Northbound exit and southbound entrance; former US 395 north
R28.77 29 Felicita Road
R30.09 30 9th Avenue, Auto Park Way
R30.63 31 Valley Parkway – Downtown Escondido
R31.52 32 SR 78Oceanside, Ramona
R32.86 33 El Norte Parkway
R33.92 34 Centre City Parkway (I-15 Bus. south) Southbound exit and northbound entrance; former US 395 south
R36.64 37 Deer Springs Road (CR S12), Mountain Meadow Road
R40.84 41 Gopher Canyon Road, Old Castle Road
R43.28 43 Old Highway 395 Former US 395
R46.49 46 SR 76Pala, Oceanside
R50.59 51 Mission Road (CR S13) – Fallbrook
R54.07 54 Rainbow Valley Boulevard
RIV R0.00-52.28
Temecula 3.44 58 SR 79 south – Temecula, Indio South end of SR 79 overlap
4.98 59 Rancho California Road, Old Town Front Street
6.62 61 SR 79 north (Winchester Road) North end of SR 79 overlap
Murrieta 8.74 63 I-215 north (Escondido Freeway) – Riverside, San Bernardino Southbound exit is via exit 64; former I-15E north / US 395 north
9.47 64 Murrieta Hot Springs Road
10.59 65 California Oaks Road
13.64 68 Clinton Keith Road
15.07 69 Baxter Road
16.30 71 Bundy Canyon Road
Lake Elsinore 19.16 73 Diamond Drive, Railroad Canyon Road
20.95 75 Main Street (I-15 Bus. north)
22.28 77 SR 74 (Central Avenue)
23.85 78 Nichols Road
26.69 81 Lake Street (I-15 Bus. south)
30.40 85 Indian Truck Trail
33.39 88 Temescal Canyon Road
35.64 90 Weirick Road
36.81 91 Cajalco Road
37.82 92 El Cerrito Road
Corona 38.69 93 Ontario Avenue
40.35 95 Magnolia Avenue
41.50 96 SR 91 (Riverside Freeway) – Riverside, Beach Cities Signed as exits 96A (east) and 96B (west) southbound; former US 91
Norco 42.88 97 Hidden Valley Parkway
43.64 98 Second Street (I-15 Bus. north)
45.60 100 Sixth Street (I-15 Bus. south)
102 Schleisman Road Proposed interchange
48.26 103 Limonite Avenue
105 Cantu-Galleano Ranch Road
51.47 106 SR 60 (Pomona Freeway) – Los Angeles, Riverside Signed as exits 106A (east) and 106B (west) northbound
San Bernardino
SBD 0.00-186.24
Ontario 1.02 108 Jurupa Street Former SR 31 south
2.39 109 I-10 (San Bernardino Freeway, I-10 Bus.) – Los Angeles, San Bernardino, Indio Signed as exits 109A (west) and 109B (east) southbound
Rancho Cucamonga 3.05 110 4th Street
5.31 112 SR 66 (Foothill Boulevard) Former US 66
6.78 113 Baseline Road
8.35 115 SR 210 (Foothill Freeway) – Pasadena, San Bernardino, Redlands Signed as exits 115A (east) and 115B (west) northbound and exits 115A (west) and 115B (east) southbound
115 Cherry Avenue Closed
Fontana 9.61 116 Summit Avenue
117 Duncan Canyon Road Proposed interchange
12.84 119 Sierra Avenue
San Bernardino 15.65 122 Glen Helen Parkway
123 I-215 south (Barstow Freeway) – San Bernardino, Riverside Left exit southbound; former I-15E south / US 91 south / US 395 south
R14.96 124 Kenwood Avenue Former US 66 east
R20.01 129 Cleghorn Road Former US 66 west
R21.37 131 SR 138Palmdale, Silverwood Lake
R28.62 138 Oak Hill Road
31.81 141 US 395 north – Adelanto, Bishop Northbound exit and southbound entrance
32.32 141 US 395 (CA).svg Joshua Street to US 395 north Southbound exit and northbound entrance
Hesperia 34.00 143 Hesperia, Phelan
Victorville 37.59 147 Bear Valley Road – Lucerne Valley
40.51 150 SR 18 west (Palmdale Road, I-15 Bus. north) South end of SR 18 overlap; former US 66 east / US 91 north
41.43 151A Roy Rogers Drive
42.03 151B Mojave Drive
43.49 153A SR 18 east (D Street, I-15 Bus. south) – Victorville, Apple Valley North end of SR 18 overlap; former US 66 / US 91
43.62 153B E Street
44.40 154 Stoddard Wells Road
47.39 157 Stoddard Wells Road – Bell Mountain
51.83 161 Dale Evans Parkway – Apple Valley
55.96 165 Wild Wash Road
60.16 169 Hodge Road
Barstow 65.84 175 Outlet Center Drive
68.77 178 Lenwood Road
70.10 179 SR 58 west – Bakersfield
71.62 181 L Street, West Main Street (I-15 Bus. north)
73.54 183 SR 247 south (Barstow Road)
74.42 184A I-40 east (Needles Freeway) – Needles Southbound exit is via exit 184
74.95 184B East Main Street (I-15 Bus. south) Signed as exit 184 southbound; former US 66 / US 91 south
76.88 186 Old Highway 58 Former SR 58 west / US 466 west
79.59 189 Fort Irwin Road Serves Fort Irwin
R81.84 191 Ghost Town Road Serves the ghost town of Calico
Yermo R84.64 194 Calico Road – Yermo
R86.38 196 Yermo Road – Yermo
R88.49 198 Minneola Road
R96.41 206 Harvard Road
R103.63 213 Field Road
R111.59 221 Afton Road
R120.42 230 Basin Road
R124.23 233 Rasor Road
Zzyzx R130.18 239 Zzyzx Road – Zzyzx
Baker R135.80 245 Baker Boulevard (I-15 Bus. north) – Baker Northbound exit and southbound entrance; former US 91 north / US 466 east
R136.57 246 SR 127 north / Kelbaker Road – Death Valley
R138.45 248 Baker Boulevard (I-15 Bus. south) – Baker Southbound exit and northbound entrance; former US 91 south / US 466 west
Halloran Springs 149.60 259 Halloran Springs Road
155.57 264 Halloran Summit Road
Cima 162.73 272 Cima Road
171.47 281 Bailey Road
176.45 286 Nipton Road
181.39 291 Yates Well Road
186.24 Nevada state line


  1. ^ Route Log- Main Routes of the Eisenhower National System of Interstate and Defense Highways - Table 1
  2. ^ CA Codes (shc:250-257)
  3. ^ CA Codes (shc:260-284)
  4. ^ Thomas Brothers. California Road Atlas and Driver's Guide [map]. (2000) p. V, 99, 106.
  5. ^ (PDF) 2007 Named Freeways, Highways, Structures and Other Appurtenances in California. Caltrans. p. 60. Retrieved 2007-03-28.  
  6. ^ Ib. at 63
  7. ^ "California Highways, Routes 9 through 16". 2007-08-30. Retrieved 2007-08-30.  
  8. ^ Interstate 15 Express Lanes
  9. ^ (PDF) 2007 Named Freeways, Highways, Structures and Other Appurtenances in California. Caltrans. p. 69. Retrieved 2007-03-28.  
  10. ^ Ib. at 63
  11. ^ Ib. at 67
  12. ^ California Highways: LRN 193
  13. ^ 1955 Gousha Los Angeles district map
  14. ^ 1963 Caltrans Los Angeles and vicinity map
  15. ^ California Highways: Interstate Highway Types and the History of California's Interstates
  16. ^ California Highways: Former State Route 31
  17. ^ 1986 Caltrans Los Angeles and vicinity map
  18. ^
  19. ^ California Department of Transportation, State Truck Route List (XLS file), accessed February 2008
  20. ^ California Department of Transportation, Log of Bridges on State Highways, July 2007
  21. ^ California Department of Transportation, All Traffic Volumes on CSHS, 2005 and 2006
  22. ^ California Department of Transportation, California Numbered Exit Uniform System, Interstate 15 Freeway Interchanges, Retrieved on 2009-02-05.
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