Ohio River

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Ohio River
Ohio River viewed from Liberty Hill in Ripley, Ohio.
Origin	Confluence of Allegheny and Monongahela at Pittsburgh
Mouth	Mississippi River at Cairo, Illinois
Basin countries	USA
Length	981 miles (1,579 km)
Source elevation	~730 feet (223 m)
Avg. discharge	248,000 cubic feet/s (7,440 m³/s) at Metropolis, Illinois
Basin area	189,422 square miles (490,603 km²)

The Ohio River is the largest tributary by volume of the Mississippi River. It is approximately 981 miles (1,579 km) long and is located in the eastern United States.

The river had great significance in the history of the Native Americans. It was a primary transportation route during the westward expansion of the early U.S. It flows through or along the border of six states, and its watershed encompasses 14 states, including many of the states of the southeastern U.S. through its largest tributary, the Tennessee River. During the eighteenth century, it was the southern boundary of the Northwest Territory, thus serving as the border between free and slave territory.

1 Geography and hydrography
- 1.1 Drainage Basin
2 Geology
- 2.1 Upper Ohio River
- 2.2 Middle Ohio River
3 History
4 Cities and towns
5 See also
6 External links
- 6.1 Maps and aerial photos

[edit] Geography and hydrography

The Allegheny and Monongahela rivers converge to form the Ohio at Point State Park in Pittsburgh

Lawrenceburg, Indiana is one of many towns that use the Ohio as a shipping avenue.

The river is formed by the confluence of the Allegheny and Monongahela rivers at Point State Park in Pittsburgh, Pennsylvania. From Pittsburgh, it flows northwest through western Pennsylvania, before making an abrupt turn to the south-southwest at the West Virginia—Ohio—Pennsylvania triple state line, from which point 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 before bending to a west-southwest course for most of its length. It flows along or through West Virginia, Kentucky, Ohio, Indiana, and Illinois, until it joins the Mississippi near the city of Cairo, Illinois.

Its watershed drains most of Tennessee and parts of Georgia, Virginia and North Carolina, via its tributaries.

Major tributaries of the river, indicated by the location of their mouth, include:

Allegheny River — Pennsylvania
Monongahela River — Pennsylvania
Beaver River— Pennsylvania
Big Wheeling Creek— West Virginia
Little Muskingum River — Ohio
Duck Creek — Ohio
Muskingum River — Ohio
Little Kanawha River — West Virginia
Hocking River — Ohio
Kanawha River — West Virginia
Guyandotte River — West Virginia
Big Sandy River — Kentucky-West Virginia border
Scioto River — Ohio
Little Miami River — Ohio
Licking River — Kentucky
Great Miami River — Ohio-Indiana border
Kentucky River — Kentucky
Green River — Kentucky
Wabash River — Indiana-Illinois border
Saline River — Illinois
Cumberland River — Kentucky
Tennessee River — Kentucky
Cache River — Illinois

[edit] Drainage Basin

Map of the Ohio River drainage basin

The Ohio's drainage basin covers 189,422 square miles (490,603 km²), including the eastern-most regions of the Mississippi Basin. States drained by the Ohio include:

Illinois (the southeast quarter of the state),
Indiana (all but the northern area of the state),
Ohio (the southern half of the state),
New York (a small area of the southern border along the headwaters of the Allegheny River),
Pennsylvania (a corridor from the southwestern corner to north central border),
Maryland (a small corridor along the Youghiogheny River on the state's western border),
West Virginia (all but the eastern panhandle of the state),
Kentucky (all but a small part in the extreme west of the state drained directly by the Mississippi River),
Tennessee (all but a small part in the extreme west of the state drained directly by the Mississippi River),
Virginia (the western border of the state),
North Carolina (the western border of the state),
Georgia (the northwest corner of the state),
Alabama (the northern portion of the state), and
Mississippi (the northeast corner of the state).

[edit] Geology

Overview of the middle Ohio River region. The river is indicated by yellow (Y) arrows and flows south and then west in this image; north is roughly straight up the image. The ancient, abandoned valleys of the Teays River can be clearly seen and are indicated by blue (B) arrows. The Scioto River is a descendant of the Teays River and is indicated by a red (R) arrow. The Kanawha River joins the Ohio River near the orange (O) arrow.

The Ohio River is young from a geologic standpoint. 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, and the modern Ohio River flows within segments of the ancient Teays. The ancient rivers were rearranged or consumed by glaciers and lakes.

[edit] Upper Ohio River

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 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, the valleys are actually found on hilltops.

[edit] Middle Ohio River

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, and eventually the upper and middle sections combined to form what is essentially the modern Ohio River.

[edit] History

Confluence of the Mississippi and Ohio Rivers at Cairo, Illinois.

Carl D. Perkins Bridge in Portsmouth, Ohio with Ohio River and Scioto River tributary on right.

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 mere tributary of the Mississippi. 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, though the forks (the confluence of the Allegheny and Monongahela rivers at what is now Pittsburgh) was considered a strategic military location.

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 both Pennsylvania and Virginia—both of whom claimed the territory—led to conflict with French forces that also claimed the region and had built forts along the Allegheny River. This led to the Seven Years' War, in which Britain gained sovereignty over the Ohio Valley.

Louisville, Kentucky, was founded at the only major natural navigational barrier on the river, the Falls of the Ohio. These were a series of rapids where the river flowed over hard, fossil-rich beds of limestone. The first locks on the river were built at Louisville to circumnavigate the falls. Today it is the site of McAlpine Locks and Dam.

Because the Ohio River flowed westwardly, it became the 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 settled at Cave-In-Rock, Illinois, waylaid travelers on their way down the river, killed them, stole their goods, and scuttled their boats. The folktales of Mike Fink recall the keelboats used for commerce in the early days of European settlement.

Other boats 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 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 it is the southern border of Ohio, Indiana, and Illinois, the Ohio River was considered a part of the border that divided free states and slave states in the years before the American Civil War. As depicted in several novels by Harriet Beecher Stowe and Toni Morrison, the Ohio River was the barrier which, by crossing by boat or on ice floes, slaves were freed. Today, the Ohio River generally separates Midwestern and Great Lakes states from Southern border states.

The charter for Virginia went not to the middle of the Ohio River, but to its far shore so the entire river was included. Wherever the river serves as a boundary between states, the river essentially belongs to the two states on the south that were divided from Virginia. 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 disputed Illinois' right to collect taxes on a riverboat casino docked in Metropolis, citing their control of the entire river.

In the early 1980s, the Falls of the Ohio National Wildlife Conservation Area was established at Louisville, Kentucky. In 2006, Cincinnati, Ohio, Indie Rock band Nevada Smith published a bootleg version of their song "Il Fiume Fluisce Colore Maronne", a humorous protest song against the pollution in the Ohio.