Washington mammals

American Beaver in Washington

Castor canadensis

Native to Washington S5 Secure in Washington

Not listed as nonindigenous in Washington by USGS NAS; native to its Washington range.

IUCN Red List status

  1. LC
  2. NT
  3. VU
  4. EN
  5. CR
  6. EW
  7. EX

LC – Least Concern

Widespread and abundant; not at risk.

Beaver swimming low in murky green pond water with only its wet head and back above the surfaceClose-up of a beaver's wet dark head swimming toward the camera through rippled waterBeaver swimming in dark rippled water with wet reddish-brown fur and a grey muzzleBeaver resting on muddy ground among reeds and a small tree trunkLarge rounded beaver back breaking the surface of a reed-lined pond
Photo: lwolfartist · CC BY 2.0Beaver swimming low in murky green pond water with only its wet head and back above the surfacePhoto: lwolfartist · CC BY 2.0Close-up of a beaver's wet dark head swimming toward the camera through rippled waterPhoto: lwolfartist · CC BY 2.0Beaver swimming in dark rippled water with wet reddish-brown fur and a grey muzzlePhoto: Ryan Hodnett · CC BY-SA 4.0Beaver resting on muddy ground among reeds and a small tree trunkPhoto: Ben · CC0Large rounded beaver back breaking the surface of a reed-lined pond

American Beaver in Washington, by the numbers

Common in Washington 10th most recorded of 145 mammals logged in Washington

3,081 occurrence records
2,954 with iNaturalist photos
Jul 12, 2026 Last seen in Washington

3,081 total records count every Washington occurrence from GBIF and iNaturalist; the map plots a georeferenced sample of 300; the monthly chart covers the 3,066 records with a full observation date.

When to look for the American Beaver in Washington

Most sightings fall in April to May.

3,066 Washington occurrence records (iNaturalist and GBIF) by month of year. Shows when the species is recorded, not a guarantee of presence.

Monthly Washington records (table)
MonthRecords
January216
February209
March320
April549
May522
June298
July213
August173
September114
October121
November169
December162

Monthly american beaver occurrence records (iNaturalist and GBIF) in Washington.

Seasonality

Year-round in Washington, with recorded sightings peaking in April–May.

Occurrence map

Where American Beaver has been recorded in Washington

300 records mapped · zoom and drag to explore

300 Washington records mapped

Notable places to look

Park, forest, or monumentiNaturalist records
Washington State Department of Natural Resources (WADNR) State Resource Management Area 39
Lake Sammamish 24
Mount St. Helens National Volcanic Monument 18
Skagit-Snoqualmie Wildlife Area Complex 18
Mount Rainier National Park 13
Gifford Pinchot National Forest 11
Olympic-Willapa Hills-South Puget Sound Wildlife Area Complex 8
Wenas Wildlife Area Complex 8

Protected places with the most american beaver sightings, from the USGS Protected Areas Database plus named mountain ranges, good spots to look, not a full breakdown, so they don't sum to the total.

Where it's recorded in Washington

CountyRecords
King County 1,669
Snohomish County 238
Whatcom County 124
Thurston County 112
Pierce County 94
Spokane County 86
Clark County 61
Kitsap County 59
Skagit County 56
Whitman County 53
Mason County 41
Grant County 39
27 other counties 449

The complete county distribution, spread across 39 Washington counties. Every occurrence record falls in one county, so these sum to the total. Counties from GBIF and US Census boundaries.

Beaver records cluster most densely around the Puget Sound lowlands and the San Juan Islands, where tidal shorelines, river deltas, and freshwater wetlands sit close together. That’s the mix of slow water and woody cover beavers need to build dams and lodges, and it shows up in the records from places like Billy Frank Jr. Nisqually National Wildlife Refuge and Mount Baker-Snoqualmie National Forest.

Beavers cut bark, twigs, and water plants, then stack the branches near a lodge as a food cache for the colder months. In Washington that habit shows up wherever slow streams and ponds meet the state’s dense conifer forest, from lowland wetlands out to slower stretches of mountain drainages.

The beaver ranks among the most frequently recorded mammals anywhere in Washington, with reports logged in every month and a spring peak in April and May. That peak likely tracks kit season and more visible daytime activity rather than a jump in numbers, and it doesn’t mean beavers are scarce elsewhere in the state.

Occurrence data from iNaturalist and GBIF.

American Beaver in other states

View all states →

Beaver swimming low in murky green pond water with only its wet head and back above the surface
Full species profile American Beaver Castor canadensis Size 60–90 cm2–3 ft Weight 11–32 kg24.3–70.5 lb Lifespan 20 yr View the full profile

More mammals in Washington in the atlas

Data & sources

The data and visualizations on this page draw on these open sources:

  • GBIFCC-BY 4.0occurrence records behind the range map, elevation, and record counts
  • iNaturalistCC0 / CC-BY / CC-BY-SAobservations, photos, and audio recordings
  • NatureServe ExplorerCC-BYthe state conservation rank
  • IUCN Red Listattributed factthe global conservation status
  • USGS NASpublic domainnative / introduced status
  • Natural Earthpublic domainthe relief basemap
  • USFSpublic domainnational-forest boundaries
  • USGS Protected Areas Databasepublic domainthe named parks, forests, and refuges behind "notable places to look"