The Black River is a river

River

A river is a natural watercourse, usually freshwater, flowing towards an ocean, a lake, a sea, or another river. In a few cases, a river simply flows into the ground or dries up completely before reaching another body of water. Small rivers may also be called by several other names, including...

 in Thurston County in the U.S. state

U.S. state

A U.S. state is any one of the 50 federated states of the United States of America that share sovereignty with the federal government. Because of this shared sovereignty, an American is a citizen both of the federal entity and of his or her state of domicile. Four states use the official title of...

 of Washington. It is approximately 25 miles (40.2 km) long with a drainage basin

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 about 144 square miles (373 km²). The Black River's source is Black Lake, located about 3 miles (4.8 km) west of Tumwater

Tumwater, Washington

Tumwater is a city in Thurston County, Washington, United States. It lies near where the Deschutes River enters Budd Inlet, the southernmost point of Puget Sound. The population was 17,371 at the 2010 census...

. The river flows generally south, through the Mima Mounds

Mima Mounds

Mima mounds is a term used for low, flattened, circular to oval, domelike, natural mounds found in the northwestern United States, Idaho, Oregon, and Washington, that are composed of loose, unstratified, often gravelly sediment that is an overthickened A Horizon...

 State Natural Area, then southwest, passing by Rochester

Rochester, Washington

Rochester is a census-designated place in Thurston County, Washington, United States. It was founded in 1852, and the 2000 census recorded its population at 1,829. According to the United States Census Bureau, the CDP has a total area of 2.3 square miles , all of it land. Rochester Schools...

 and entering Grays Harbor County

Grays Harbor County, Washington

Grays Harbor County is a county in the state of Washington, in the United States of America. As of 2010, the population was 72,797. The county seat is at Montesano, and its largest city is Aberdeen. The county is named after a large estuarine bay near its southwestern corner...

, then emptying into the Chehalis River in the Chehalis Indian Reservation

Chehalis (tribe)

The Chehalis people are a native people of westernWashington state in the United States. They should not be confused with the similarly named Chehalis First Nation of the Harrison River in the Fraser Valley area of British Columbia....

.

The fur trader John Work was the first to describe the Black River in 1824: The Black River so named from the colour of its water . . . A great many dead salmon are in the river, and many that are just alive and barely able to move through the water.

The Black River Unit of the Nisqually National Wildlife Refuge

Nisqually National Wildlife Refuge

The Nisqually National Wildlife Refuge is a wildlife preserve operated by the United States Fish and Wildlife Service on the Nisqually River Delta near Puget Sound in northeastern Thurston County, Washington and northwestern Pierce County, Washington...

extends about 5 miles (8 km) along the river immediately south of Black Lake.