The river had great significance in the history of the Native Americans, as numerous civilizations formed along its valley. In the last five centuries prior to European contact, the Mississippian culture built numerous regional chiefdoms and major earthwork mounds in the Ohio Valley, such as Angel Mounds near Evansville, Indiana. For thousands of years, Native Americans, like the European explorers and settlers who followed them, used the river as a major transportation and trading route. About 1200 CE, the area of Kentucky was the site of longterm wars between the Iroquois, invading from present-day New York, and the Osage and other Ohio River tribes. Over centuries, the Osage, Omaha, Ponca and Kaw migrated west of the Mississippi River, settling by the mid-17th century in their historic grounds in Missouri, Arkansas, and Oklahoma and nearby states.
After European-American settlement, the river served at times as a border between present-day Kentucky and Indian Territories. It was a primary transportation route during the westward expansion of the early U.S. The Ohio flows through or along the border of six states, and its drainage basin encompasses 14 states. Through its largest tributary, the Tennessee River, the basin includes many of the states of the southeastern U.S.
During the 19th century, the river was the southern boundary of the Northwest Territory, thus serving as the border between free and slave territory. It is sometimes referred to as the "Mason-Dixon line". It is commonly acknowledged as the western natural extension of the original Mason-Dixon line that divided Pennsylvania and Delaware from Maryland and West Virginia (then a part of Virginia). It was thus the unofficial and, at times disputed, border between the Northern United States and the American South or Upper South.
The Ohio River is a climatic transition area, as its water runs along the periphery of the humid subtropical climate and humid continental climate. It is inhabited by fauna and flora of both climates. In his Notes on the State of Virginia published in 1781-82, Thomas Jefferson stated: "The Ohio is the most beautiful river on earth. Its current gentle, waters clear, and bosom smooth and unbroken by rocks and rapids, a single instance only excepted."
The river is formed by the confluence of the Allegheny and Monongahela rivers. Point State Park in Pittsburgh, Pennsylvania marks the confluence. From Pittsburgh, it flows northwest through Allegheny and Beaver counties, before making an abrupt turn to the south-southwest at the West Virginia—Ohio—Pennsylvania triple-state line (near East Liverpool, Ohio, Chester, West Virginia, and Midland, Pennsylvania). From there, it forms the border between West Virginia and Ohio, upstream of Wheeling, West Virginia.
The river then follows a roughly southwest and then west-northwest course until Cincinnati, before bending to a west-southwest course for most of its length. It flows along the borders of West Virginia, Ohio, Kentucky, Indiana and Illinois, until it joins the Mississippi near the city of Cairo, Illinois.
Major tributaries of the river, indicated by the location of the mouths, include:
The Ohio's drainage basin covers 189,422 square miles (490,603 km²), including the easternmost regions of the Mississippi Basin. States drained by the Ohio include:
From a geologic standpoint, the Ohio River is young. The river formed on a piecemeal basis beginning between 2.5 and 3 million years ago. The earliest Ice Ages occurred at this time and dammed portions of north-flowing rivers. The Teays River was the largest of these rivers. The modern Ohio River flows within segments of the ancient Teays. The ancient rivers were rearranged or consumed by glaciers and lakes.
The upper Ohio River formed when one of the glacial lakes overflowed into a south-flowing tributary of the Teays River. Prior to that event, the north-flowing Steubenville River (no longer in existence) ended between New Martinsville and Paden City, West Virginia. Likewise, the south-flowing Marietta River (no longer in existence) ended between the present-day cities. The overflowing lake carved through the separating hill and connected the rivers.
The resulting floodwaters enlarged the small Marietta valley to a size more typical of a large river. The new large river subsequently drained glacial lakes and melting glaciers at the end of several Ice Ages. The valley grew with each major Ice Age.
Many small rivers were altered or abandoned after the upper Ohio River formed. Valleys of some abandoned rivers can still be seen on satellite and aerial images of the hills of Ohio and West Virginia between Marietta, Ohio, and Huntington, West Virginia. As testimony to the major changes that occurred, such valleys are found on hilltops.
The middle Ohio River formed in a manner similar to formation of the upper Ohio River. A north-flowing river was temporarily dammed southwest of present-day Louisville, Kentucky, creating a large lake until the dam burst. A new route was carved to the Mississippi River. Eventually the upper and middle sections combined to form what is essentially the modern Ohio River.
Since it was considered by pre-Columbian inhabitants of eastern North America to be part of a single river continuing on through the lower Mississippi, it is perhaps an understatement to characterize the Ohio as a tributary of the Mississippi River. The river is 981 miles (1,579 km) long and carries the largest volume of water of any tributary of the Mississippi. The Indians and early explorers and settlers of the region often considered the Allegheny to be part of the Ohio. The forks (the confluence of the Allegheny and Monongahela rivers at what is now Pittsburgh) was considered a strategic military location.
In 1669 René-Robert Cavelier, Sieur de La Salle, led an expedition of French traders who became the first Europeans to see the river. He traveled from Canada and entered the headwaters of the Ohio, traveling as far as the Falls of Ohio before turning back. He returned to explore the river again in other expeditions. An Italian cartographer traveling with him created the first map of the Ohio River. France claimed ownership of the river until its territory in North America was ceded to Great Britain in 1763, following the Seven Years War (aka the French and Indian War.)
On May 19, 1749, King George II of Great Britain granted the Ohio Company a charter of land around the forks. Exploration of the territory and trade with the Indians in the region near the Forks by British colonials from Pennsylvania and Virginia—both of which claimed the territory—led to conflict with French forces that also claimed the region and had built forts along the Allegheny River. This directly led to the French and Indian War in North America. The French and Indian War was part of a more global conflict, the Seven Years' War between England and France. After several initial defeats, the British eventually gained sovereignty over the Ohio Valley.
The 1768 Treaty of Fort Stanwix opened Kentucky to colonial settlement and established the Ohio River as a southern boundary for American Indian territory. In 1774, the Quebec Act restored the land east of the Mississippi River and north of the Ohio River to Quebec, appeasing the French-speaking British subjects, but angering the Thirteen Colonies. They listed it as one of the Intolerable Acts which precipitated the American Revolution.
Louisville, Kentucky was founded at the only major natural navigational barrier on the river, the Falls of the Ohio. The Falls were a series of rapids where the river dropped 26 feet (7.9 m) in a stretch of about 2 miles (3.2 km). In this area, the river flowed over hard, fossil-rich beds of limestone. The first locks on the river were built in 1825 at Louisville to circumnavigate the falls. Today it is the site of McAlpine Locks and Dam.
Because the Ohio River flowed westwardly, it became a convenient means of westward movement by pioneers traveling from western Pennsylvania. After reaching the mouth of the Ohio, settlers would travel north on the Mississippi River to St. Louis, Missouri. There, some continued on up the Missouri River, some up the Mississippi, and some further west over land routes. In the early 19th century, pirates such as Samuel Mason, settled at Cave-In-Rock, Illinois, waylaid travelers on their way down the river. They killed travelers, stealing their goods and scuttling their boats. The folktales about Mike Fink recall the keelboats used for commerce in the early days of European settlement. The Ohio River boatmen were the inspiration for performer Dan Emmett, who in 1843 wrote the song "The Boatman's Dance".
Trading boats and ships traveled south on the Mississippi to New Orleans, and sometimes beyond to the Gulf of Mexico and other ports in the Americas and Europe. This provided a much-needed export route for goods from the west, since the trek east over the Appalachian Mountains was long and arduous. The need for access to the port of New Orleans by settlers in the Ohio Valley led to the Louisiana Purchase in 1803.
Because the river is the southern border of Ohio, Indiana and Illinois, it was part of the border between free states and slave states in the years before the American Civil War. The expression "sold down the river" originated as a lament of Upper South slaves, especially from Kentucky, who were separated from their families and sold in Louisville and other Kentucky locations to be shipped via the Ohio River and Mississippi down to New Orleans. There they were sold to owners of cotton and sugar field plantations in the Deep South, which were notoriously hard on laborers. Before and during the Civil War, the Ohio River was called the "River Jordan" by slaves' crossing it to escape to freedom in the North via the Underground Railroad. Such escapes were depicted in contemporary anti-slavery novels, such as Harriet Beecher Stowe's Uncle Tom's Cabin. The times have also been portrayed by late 20th century novelists such as Toni Morrison. More escaping slaves made their perilous journey north to freedom across the Ohio River than anywhere else across the north-south frontier.
The charter for Virginia went to the far shore of the Ohio River, so that the entire river was included in the lands "owned" by Virginia. Where the river serves as a boundary between states today, the entire river belongs to the states on the east and south, i.e., West Virginia and Kentucky, that were divided from Virginia. Thus Wheeling Island, the largest inhabited island in the Ohio River, belongs to West Virginia, even though it is closer to the Ohio shore than to the West Virginia shore. Kentucky brought suit against Indiana in the early 1980s because of the building of the Marble Hill nuclear power plant in Indiana, which would have discharged its waste water into the river.
The U.S. Supreme Court held that Kentucky's jurisdiction (and, implicitly, that of West Virginia) extended only to the low-water mark of 1793 (important because the river has been extensively dammed for navigation, so that the present river bank is north of the old low-water mark.) Similarly, in the 1990s, Kentucky challenged Illinois' right to collect taxes on a riverboat casino docked in Metropolis, citing its own control of the entire river. A private casino riverboat that docked in Evansville, Indiana on the Ohio River opened about the same time. Although such boats cruised on the Ohio River in an oval pattern up and down, the state of Kentucky soon protested. Other states had to limit their cruises to going forwards then reversing and going backwards on the Indiana shore only.
In the early 1980s, the Falls of the Ohio National Wildlife Conservation Area was established at Clarksville, Indiana.
The Ohio River is a naturally shallow river that was artificially deepened by series of dams. The natural depth of the river varied from about 3 feet to 40 feet. The dams raise the water level and have turned the river largely into a series of reservoirs, eliminating shallow stretches and allowing for commercial navigation. From its origin to Cincinnati, the average depth is approximately 27 feet (8 m). The maximum depth is below the McAlpine Locks and Dam at the Falls of the Ohio at Louisville, Kentucky where flood stage is reached when the water reaches 55 feet (17 m) on the lower gage. From Louisville, the river loses depth very gradually until its confluence with the Mississippi at Cairo, Illinois, where it has an approximate depth of 20 feet (6 m). Water levels for the Ohio River are predicted daily by the National Oceanic and Atmospheric Administration's Ohio River Forecast Center. The water depth predictions are relative to each local flood plain based upon predicted rainfall in the Ohio River basin in five reports as follows:
Cities along the Ohio include:
The world record for the largest blue catfish 104 pounds (47.2 kilograms) taken in the line class was set on the Ohio River in 1999. The river also holds records for the following species for the state of Kentucky:
The Ohio River from Cairo, Illinois to Smithland, Kentucky comprises a significant portion of the Great Loop, the circumnavigation of Eastern North America by water for recreational purposes.
OHIO RIVER, the principal eastern tributary of the Mississippi river, U.S.A. It is formed by the confluence of the Allegheny and Monongahela rivers at Pittsburg, Pennsylvania, and flows N.W. nearly to the W. border of Pennsylvania, S.S.W. between Ohio and West Virginia, W. by N. between Ohio and Kentucky, and W.S.W. between Indiana and Illinois on the N. and Kentucky on the S. It is the largest of all the tributaries of the Mississippi in respect to the amount of water discharged (an average of about 158,000 cub. ft. per sec.), is first in importance as a highway of commerce, and in length (967 m.) as well as in the area of its drainage basin (approximately 2 10,000 sq. m.) it is exceeded only by the Missouri. The slope of the river at low water ranges from 1 ft. or more per mile in the upper section to about o. 75 ft. per mile in the middle section and 0.29 ft. per mile in the lower section, and the total fall is approximately 50o ft. Nearly twothirds of the - bed is occupied by 187 pools, in which the fall is very gentle; and the greater part of the descent is made over intervening bars, which are usually composed of sand or gravel but occasionally of hard pan or rock. The greatest falls are at Louisville, where the river within a distance of 2.25 m. descends 23.9 ft. over an irregular mass of limestone. The rock floor of the valley is usually 30 to 50 ft. below low water level, and when it comes to the surface, as it occasionally does, it extends at this height only part way across the valley. In the upper part of the river the bed contains much coarse gravel and numerous boulders, but lower down a sand bed prevails. The ordinary width of the upper half of the river is quite uniform, from 1200 to 150o ft., but it widens in the pool above Louisville, contracts immediately below the Falls, and then gradually widens again until it reaches a maximum width of more than a mile about 20 m. from its mouth. Islands are numerous and vary in size from an acre or less to 5000 acres; above Louisville there are fifty or more, and below it about thirty. Many of them are cultivated.
Besides its parent streams, the Allegheny and the Monongahela, the Ohio has numerous large branches. On the N. it receives the waters of the Muskingum, Scioto, Miami and Wabash rivers, and on the S. those of the Kanawha, Big Sandy, Licking, Kentucky, Green, Cumberland and Tennessee rivers.
The drainage basin of the Ohio, in which the annual rainfall averages about 43 in., is, especially in the S. part of the river, of the "quick-spilling" kind, and as the swift mountain streams in that section are filled in February or March by the storms from the Gulf of Mexico, while the northern streams are swollen by melting snow and rain, the Ohio rises very suddenly and not infrequently attains a height of 30 to 50 ft. or more above low water level, spreads out ten to fifteen times its usual width, submerges the bottom lands, and often causes great damage to property in the lower part of the cities along its banks.
Robert Cavelier, Sieur de La Salle, asserted that he discovered the Ohio and descended it until his course was obstructed by a fall (thought to be the Falls at Louisville); this was probably in 1670, but until the middle of the next century, when its strategic importance in the struggle of the French and the English for the possession of the interior of the continent became fully recognized, little was generally known of it. By the treaty of 1763 ending the Seven Years' War the English finally gained undisputed control of the territory along its banks. After Virginia had bought, in 1768, the claims of the Six Nations to the territory south of the Ohio, immigrants, mostly Virginians, began to descend the river in considerable numbers,' but the Shawnee Indians, whose title to the land was more plausible than that of the Six Nations ever was, resisted their encroachments until the Shawnees were defeated in October 1774 at the battle of Point Pleasant. By the treaty of 1783 the entire Ohio country became a part of the United States and by the famous Ordinance of 1787 the north side was opened to settlement. Most of the settlers entered the region by the headwaters of the Ohio and carried much of their market produce, lumber, &c., down the Ohio and Mississippi to New Orleans or beyond. Until the successful navigation of the river by steamboats a considerable portion of the imports was carried overland from Philadelphia or Baltimore to Pittsburg. The first steamboat on the Ohio was the "New Orleans," which was built in 1811 by Nicholas J. Roosevelt and sailed from Pittsburg to New Orleans in the same year, but it remained for Captain Henry M. Shreve (1785-1854) to demonstrate with the "Washington," which he built in 1816, the success of this kind of navigation on the river. From 1820 to the Civil War the steamboat on the system of inland waterways of which the Ohio was a part was a dominant factor in the industrial life of the Middle West. Cincinnati, Louisville and Pittsburg on its banks were extensively engaged in building these vessels. The river was dotted with floating shops - drygoods boats fitted with counters, boats containing a tinner's establishment, a blacksmith's shop, a factory, or a lottery office. Until the Erie Canal was opened in 1825 the Ohio river was the chief commercial highway between the East and the West. It was connected with Lake Erie in 1832 by the Ohio & Erie Canal from Portsmouth to Cleveland, and in 1845 by the Miami & Erie Canal from Cincinnati to Toledo.
In the natural state of the river navigation was usually almost wholly suspended during low water from July to November, and it was dangerous at all times on account of the numerous snags. The Federal government in 1827 undertook to remove the snags and to increase the depth of water on the bars by the construction of contraction works, such as dikes and wing dams, and appropriations for these purposes as well as for dredging were continued until 1844 and resumed in 1866; but as the channel obtained was less than 3 ft. in 1870, locks with movable dams - that is, dams that can be thrown down on the approach of a flood - were then advocated, and five years later Congress made an appropriation for constructing such a dam, the Davis Island Dam immediately below Pittsburg, as an experiment. This was opened in 1885 and was a recognized success; and in 1895 the Ohio Valley Improvement Association was organized in an effort to have the system extended. At first the association asked only for a channel 6 ft. in depth; and between 1896 and 1905 Congress authorized the necessary surveys and made appropriations for thirty-six locks and dams from the Davis Island Dam to the mouth of the Great Miami river. As the association then urged that the channel be made 9 ft. in depth Congress authorized the secretary of war to appoint a board of engineers which should make a thorough examination and report on the comparative merits of a channel 9 ft. in depth, and one 6 ft. in depth. The board reported in 1908 in favour of a 9-ft. channel and stated that fifty-four locks and dams would be necessary for such a channel throughout the course of the river, and Congress adopted this project. At the Falls is the Louisville & Portland Canal, originally built by a private corporation, with the United States as one of the stockholders, and opened in 1830, with a width of 50 ft., a length of 200 ft., and three locks, each with a lift of about 83 ft. In1860-1872the width was increased to 90 ft. and the three old locks were replaced by two new ones. The United States gradually increased its holdings of stock until in 1855 it became owner of all but five shares; it assumed the management of the canal in 1874, abolished tolls in 1880, and thereafter improved it in many respects. Sixty-eight locks and dams have been constructed on the principal tributaries, and the Allegheny, Monongahela, Cumberland, Tennessee, Muskingum, Kanawha, Little Kanawha, Big Sandy, Wabash, and Green now afford a total of about 960 m. of slack-water navigation.
See the Board of Engineers' Report of Examination of Ohio River with a view to obtaining Channel Depths of 6 and 9 ft. respectively (Washington, 1908); A. B. Hulbert, Waterways of Westward Expansion (Cleveland, 1903) and The Ohio River, a Course of Empire (New York, 1906); also R. G. Thwaites, Afloat on the Ohio (New York, 1900).
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The Ohio River is the one of the most important tributaries to the Mississippi River. It is 981 miles long. It forms boundaries for the states of Ohio, Kentucky, Illinois, Indiana, and West Virginia before finally going to its headwaters in Pennsylvania. It is its widest a little to the left of downtown Louisville, where it is one mile wide. Cities on the Ohio River include Paducah, Kentucky, Cincinnati, Ohio, Pittsburgh, Pennsylvania. The river begins in Pittsburgh. The Wabash, Kentucky and the Tennessee Rivers flow into the Ohio.