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, 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 nineteenth 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."
Geography and hydrography
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:
- Allegheny
River — Pittsburgh, Pennsylvania

- Kinniconick
Creek - Vanceburg, Kentucky

- Monongahela
River — Pittsburgh, Pennsylvania

- Chartiers
Creek - Pittsburgh, Pennsylvania

- Beaver River
— Rochester, Pennsylvania
- Wheeling Creek — Wheeling,
West Virginia

- Little Muskingum River —
Ohio
- Duck Creek — Ohio
- Muskingum
River — Marietta,
Ohio

- Little
Kanawha River — Parkersburg, West Virginia

- Hocking River —
Hockingport,
Ohio

- Kanawha River —
Point
Pleasant, West Virginia

- Guyandotte
River — Huntington, West Virginia

- Big Sandy River —
Kentucky-West Virginia border
- Little Sandy River - Greenup,
Kentucky

- Scioto River —
Portsmouth,
Ohio

- Little Miami River
— Cincinnati, Ohio
- Licking
River — Newport
-Covington
, Kentucky
- Great Miami River
— Ohio-Indiana border
- Salt
River — West
Point, Kentucky

- Kentucky River
— Carrollton,
Kentucky

- Green River —
Kentucky
- Wabash River — Indiana-Illinois
border
- Saline River —
Illinois
- Cumberland
River — Smithland, Kentucky

- Tennessee
River — Paducah,
Kentucky

- Cache River —
Illinois
Drainage basin
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:
- 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
and a small area in the southeastern corner of the state which is
drained by the Conasauga
River),
- Virginia
(most of Southwest
Virginia),
- North Carolina
(the western quarter 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).
Geology
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.
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
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.
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. Eventually the upper
and middle sections combined to form what is essentially the modern
Ohio River.
History
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 in a stretch of about . 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 tates 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.
Today,
the Ohio River is considered to separate Midwestern Great Lakes
states from Southern states which were
historically border states in the
Civil War.

Mouth of the Ohio, as it feeds into
the Mississippi
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
.
River depth
The Ohio River is a naturally shallow river that was artificially
deepened by series of
dams. 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. Near its origin at the
confluence of the
Allegheny and
Monongahela Rivers, the Ohio
remains fairly shallow, never rising above around deep all the way
past Cincinnati. From its origin to Cincinnati, the average depth
is approximately . However, once past Cincinnati, the river deepens
substantially.
Due to the damming, along with glacier formations and migrations in the latter part
of the second Ice Age, the river's
depth increases nearly fivefold over about , coming to a maximum
depth of just west of Louisville, Kentucky
. The around Louisville represent the deepest
area of the river with an average depth of approximately , allowing
for much larger vessels to traverse the river.
From Louisville, the
river loses its depth very gradually until its confluence with the
Mississippi at Cairo,
Illinois
, where it
has an approximate depth of , because it is more free
flowing. The natural depth of the river varies from about 3
feet to 40 feet.
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:
- Pittsburgh, Pennsylvania
, to Hannibal Dam, Ohio
(including the Allegheny and Monongahela rivers) (click to see report)
- Willow Island Dam, Ohio, to
Greenup Dam, Kentucky (including the
Kanawha River) (click to see report)
- Portsmouth, Ohio, to Markland
Locks and Dam
, Kentucky (click to see report)
- McAlpine Locks and Dam
, Kentucky, to Cannelton
Locks and Dam
, Indiana (click to see report)
- Newburgh Dam,
Indiana, to Golconda,
Illinois
(click to see report)
Cities and towns along the river
Cities along the Ohio include:
Recreation
The
world record for the largest
blue catfish 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.
See also
References
External links