Today’s Washington counties did not always exist in the present form. They went through many different changes in the space of a few short years. Washington Counties were first formed while part of the Oregon Territory, and after that the Washington Territory.

Washington Territorial Counties

The first counties were created from unorganized territory in 1845. Eight of the counties were created by Oregon governments prior to the organization of Washington Territory, 26 were created during Washington’s territorial period, and five were created after Washington became a state.

The Territory of Washington was an organized on March 2, 1853, when it split from Oregon Territory. On March 4, 1863, the Idaho Territory was split off.

The State of Washington was admitted the union as the 42nd state on November 11, 1889.

Washington Counties Today

Today, Washington is divided into 39 counties.  States bordering Washington are IdahoOregon and Canada.

Fun Facts about Washington Counties

Counties by Year

  • Lewis and Clark Counties was the original 2 counties created on December 21, 1845.
  • Pend Oreille County was the last county created on March 01, 1911.

County Size Facts

County Population Facts

  • Garfield County (2,225) is the least populated county in Washington.
  • King County (2,252,782) is the most populated county in Washington.

Washington City Facts

Washington’s 10  largest cities (2018 est.) are:

  1. Seattle (744,955) is in King County
  2. Spokane (219,190) is in Spokane County
  3. Tacoma (216,279) is in Pierce County
  4. Vancouver (183,012) is in Clark County
  5. Bellevue (147,599) is in King County
  6. Kent (129,618) is in King County
  7. Everett (111,262) is in Snohomish County
  8. Renton (102,153) is in King County
  9. Spokane Valley (99,703) is in Spokane County
  10. Federal Way (97,044) is in King County

Boundary Changes of Washington Counties from 1843-1915

This Interactive Map of Washington Counties show the historical boundaries, names, organization, and attachments of every county, extinct county and unsuccessful county proposal from 1843 to 1915.

List of Washington Counties

List of Old Former / Extinct Washington Counties

At least 4 Washington counties that were established no longer exist. A lot of these counties were established and disbanded within the 19th century; county borders have modified very little since 1900 in the vast most of states.

The below counties formerly within the area of the State of Washington no longer exist:

  • Chehalis County – Formed in 1854 (renamed Grays Harbor, 1915) Thurston.
  • Slaughter County – formed in 1857 and renamed Kitsap County in 1857.
  • Sawamish County – formed in 1854 and renamed Mason County in 1864.
  • Spokane County (old) – formed in 1859, abolished and became part of Stevens County in 1864; In 1879 part of this county was set off as Present Spokane County

COUNTY County, Washington

Created on DATE from LAND. COUNTY County was renamed to COUNTY County on November 7, 1907.

Scroll to Top