CogKnoSys

Knowledge you can walk. Read the idea below, then step up to the general, across to peers or down to the specific.

Physical

Ridgefield National Wildlife Refuge

Ridgefield National Wildlife Refuge is a protected wildlife area on the Columbia River, west of Ridgefield, Washington, that shelters resident and migrating birds.

See it on the map

Learn, discuss, create, buy or invest

The idea

Ridgefield National Wildlife Refuge is a protected natural area overseen by the United States Fish and Wildlife Service. It borders the Columbia River just west of the city of Ridgefield, Washington, and Lake River splits it in two. The refuge protects marshes, grasslands and woodlands.

A wildlife refuge is land set aside mainly so that wild animals and plants have a safe place to live, feed and raise their young. Ridgefield gives many kinds of birds a home all year and a resting stop during their long migrations. Sandhill cranes, tundra swans, shorebirds and many songbirds pass through in spring and fall. Great blue herons, bald eagles and ospreys live here all year and nest on the refuge. Black-tailed deer and cougars are the largest mammals that roam its land.

In 2023 the River 'S' Unit recorded 239 bird species, ranking the refuge 15th in the state for bird diversity. Beginning in 2012, about 50 Columbian white-tailed deer were moved to the refuge by helicopter from another refuge. That move is considered part of why the deer's population doubled to over 900 in the Lower Columbia River basin by 2015. The increase led to a recommendation that the deer be reclassified from endangered to threatened.

Check yourself

Question 1 of 3

In 2023, how many bird species did the refuge's River 'S' Unit record?

Pick one. The first pick counts.

Composition

what it's made of

  • Carty Unit — Managed to conserve the natural Columbia River floodplain, with a 2-mile self-guided hiking trail.
  • River 'S' Unit — Reached by a 4.2-mile auto tour route and the 1.2-mile Kiwa Hiking Trail.
  • Bachelor Island Unit — Managed, like River 'S', to give waterfowl and other wetland wildlife as much habitat as possible.
  • Historic quarries — Seven historic quarries in the Carty Unit, listed on the National Register of Historic Places.

Connection

how it relates

Under Lower Columbia Ecosystems and Wildlife

In place

  1. Ridgefield, Washingtonstrength 80 of 100

    The refuge lies just west of the city of Ridgefield, Washington.

  2. Columbia Riverstrength 80 of 100

    The refuge borders the Columbia River.

  3. Sauvie Islandstrength 40 of 100

    Columbian white-tailed deer from the refuge have been recorded swimming to Sauvie Island.

Cause and effect

  1. Habitatsstrength 70 of 100

    The refuge protects marsh, grassland and woodland habitats for wildlife.

  2. Biodiversitystrength 60 of 100

    The refuge supports rich bird diversity, with 239 species recorded in one unit in 2023.

Change

how and why it evolves

Past
The refuge was established in 1965 to provide vital winter habitat for wintering waterfowl, with an emphasis on the dusky Canada goose.
Now
Its Community Nature Center at the Carty Unit opened in May 2026 as an educational space with displays, a classroom and meeting rooms.
Next
The refuge will likely keep serving as a key stopover for migrating birds while welcoming more students and visitors to learn about nature.

Knowledge you can walk. Read the idea, then step up, across or down.

Ridgefield National Wildlife Refuge

Ridgefield National Wildlife Refuge is a protected wildlife area on the Columbia River, west of Ridgefield, Washington, that shelters resident and migrating birds.

See it on the map

Learn, discuss, create, buy or invest

The idea

Ridgefield National Wildlife Refuge is a protected natural area overseen by the United States Fish and Wildlife Service. It borders the Columbia River just west of the city of Ridgefield, Washington, and Lake River splits it in two. The refuge protects marshes, grasslands and woodlands.

A wildlife refuge is land set aside mainly so that wild animals and plants have a safe place to live, feed and raise their young. Ridgefield gives many kinds of birds a home all year and a resting stop during their long migrations. Sandhill cranes, tundra swans, shorebirds and many songbirds pass through in spring and fall. Great blue herons, bald eagles and ospreys live here all year and nest on the refuge. Black-tailed deer and cougars are the largest mammals that roam its land.

In 2023 the River 'S' Unit recorded 239 bird species, ranking the refuge 15th in the state for bird diversity. Beginning in 2012, about 50 Columbian white-tailed deer were moved to the refuge by helicopter from another refuge. That move is considered part of why the deer's population doubled to over 900 in the Lower Columbia River basin by 2015. The increase led to a recommendation that the deer be reclassified from endangered to threatened.

Check yourself

3 quick questions, instant feedback.