The Black River is a tributary

Tributary

A tributary or affluent is a stream or river that flows into a main stem river or a lake. A tributary does not flow directly into a sea or ocean...

 of Lake Erie

Lake Erie

Lake Erie is the fourth largest lake of the five Great Lakes in North America, and the tenth largest globally. It is the southernmost, shallowest, and smallest by volume of the Great Lakes and therefore also has the shortest average water residence time. It is bounded on the north by the...

, about 12 mi (19 km) long, in northern Ohio

Ohio

Ohio is a Midwestern state in the United States. The 34th largest state by area in the U.S.,it is the 7th‑most populous with over 11.5 million residents, containing several major American cities and seven metropolitan areas with populations of 500,000 or more.The state's capital is Columbus...

 in the United States

United States

The United States of America is a federal constitutional republic comprising fifty states and a federal district...

. Via Lake Erie, the Niagara River

Niagara River

The Niagara River flows north from Lake Erie to Lake Ontario. It forms part of the border between the Province of Ontario in Canada and New York State in the United States. There are differing theories as to the origin of the name of the river...

 and Lake Ontario

Lake Ontario

Lake Ontario is one of the five Great Lakes of North America. It is bounded on the north and southwest by the Canadian province of Ontario, and on the south by the American state of New York. Ontario, Canada's most populous province, was named for the lake. In the Wyandot language, ontarío means...

, it is part of the watershed

Drainage basin

A drainage basin is an extent or an area of land where surface water from rain and melting snow or ice converges to a single point, usually the exit of the basin, where the waters join another waterbody, such as a river, lake, reservoir, estuary, wetland, sea, or ocean...

 of the St. Lawrence River, which flows to the Atlantic Ocean

Atlantic Ocean

The Atlantic Ocean is the second-largest of the world's oceanic divisions. With a total area of about , it covers approximately 20% of the Earth's surface and about 26% of its water surface area...

. The Black drains an area of 470 mi² (1217 km²).

According to the Geographic Names Information System

Geographic Names Information System

The Geographic Names Information System is a database that contains name and locative information about more than two million physical and cultural features located throughout the United States of America and its territories. It is a type of gazetteer...

, the Black River has also been known historically as "Canesadooharie River" and as "Riviere en Grys." It was known as "Canesadooharie" -- River of Many Pearls -- by the Wyandot.

Course

The Black River is formed in the city of Elyria

Elyria, Ohio

-Community:Elyria has an extensive, although financially burdened, community food pantry and "Hot Meals" program administered through the Second Harvest Food Bank and several churches Elyria is served by Elyria Memorial Hospital.-Recreation and parks:...

 by the confluence of its east and west branches:

• The East Branch Black River is formed in northwestern Medina County by the confluence of two short tributaries, the East Fork Black River and the West Fork East Branch Black River. The East Fork flows southwardly past Lodi
  Lodi, Ohio
  Lodi is a village in Medina County, Ohio, United States. The population was 3,061 at the 2000 census.- History :Founded in 1811, Lodi is the oldest settlement in Medina County. It was originally called Harrisville, in honor of the family that founded it. It was later renamed to Lodi, the Indian...
  
   before turning northwestwardly, and the West Fork rises in northeastern Ashland County
  Ashland County, Ohio
  Ashland County is a county located in the state of Ohio, United States, and was formed in 1846 from parts of Huron, Lorain, Richland and Wayne Counties. As of the 2010 census, the population was 53,139. Its county seat is Ashland...
  
   and flows generally eastwardly into Medina County; the two join about 1 mi (2 km) northwest of Lodi, and the East Branch then flows generally northwardly into Lorain County
  Lorain County, Ohio
  Lorain County is a county located in the U.S. state of Ohio, and is considered to be a part of what is locally referred to as Greater Cleveland. As of the 2010 census, its population was 301,356. an increase from 284,664 in 2000...
  
  , past Grafton
  Grafton, Ohio
  Grafton is a village in Lorain County, Ohio, United States, along the East Branch of the Black River. The population was 2,302 at the 2000 census...
  
  . It drains an area of 222 mi² (575 km²).
• The West Branch Black River, about 30 mi (48 km) long, rises in northern Ashland County and flows generally northeastwardly into Lorain County, past Rochester
  Rochester, Ohio
  Rochester is a village in Lorain County, Ohio, United States, along the West Branch of the Black River. The population was 190 at the 2000 census.-Geography:Rochester is located at ....
  
  . It drains an area of 174 mi² (451 km²).

From the confluence of the branches in Elyria, the Black River flows generally northwardly past Sheffield

Sheffield, Ohio

-Notable residents:* Lee Richmond - a 19th century major league baseball pitcher, was born in Sheffield....

 into the city of Lorain

Lorain, Ohio

Lorain is a city in Lorain County, Ohio, United States. The municipality is located in northeastern Ohio on Lake Erie, at the mouth of the Black River, about 30 miles west of Cleveland....

, where it enters Lake Erie. The mouth of the river forms part of the harbor

Harbor

A harbor or harbour , or haven, is a place where ships, boats, and barges can seek shelter from stormy weather, or else are stored for future use. Harbors can be natural or artificial...

of Lorain.