San Juan County is a county in the Salish Sea in the far northwestern corner of the U.S. state of Washington. As of the 2020 census, its population was 17,788. The county seat and only incorporated town is Friday Harbor, on San Juan Island. The county was formed on October 31, 1873, from Whatcom County and is named for the San Juan Islands, which are in turn named for Juan Vicente de Güemes, 2nd Count of Revillagigedo, the Viceroy of New Spain.
Although the islands have no state highways, the ferry routes serving them are designated as part of the state highway system.
History
The San Juan Islands were the subject of a territorial dispute between Great Britain and the United States from 1846 to 1872, leading to the Pig War in 1859. The bloodless conflict ended through arbitration led by Kaiser Wilhelm I, which awarded the islands to the United States. San Juan County was home to Henry Cayou, one of the first elected officials of Native descent in Washington.
On June 7, 2024, a T-34 plane flown by former astronaut and Air Force pilot William Anders crashed in the San Juan Islands. Anders did not survive the crash.
Geography
According to the United States Census Bureau, the county has a total area of , of which is land and (72%) is water. It is the smallest county in Washington by land area and fourth-smallest by total area.
San Juan County is a cluster of more than 400 islands and rocks with elevations above mean high tide. 134 of these islands and rocks are named. The county has a rugged, rocky shoreline and several mountains. The highest point in the county is Mount Constitution on Orcas Island at above sea level.
Geographic features
- Boundary Pass
- Haro Strait
- Rosario Strait
- San Juan Islands
- Strait of Georgia
- Strait of Juan de Fuca
Major islands
There are approximately 743 islands and rocks in the San Juan Island chain. Most of the county's population lives on the largest four islands, which are the only county islands served by the Washington State Ferries. The four largest islands are:
- Orcas Island ()
- San Juan Island ()
- Lopez Island ()
- Shaw Island ()
- Blakely Island
- Crane Island
- Decatur Island
Adjacent counties
- Whatcom County – northeast
- Skagit County – east
- Island County – southeast
- Jefferson County – south
- Clallam County – south/southwest
- Capital Regional District, British Columbia – west
National protected areas
- San Juan Island National Historical Park
- San Juan Islands National Wildlife Refuge
- San Juan Islands National Monument
- San Juan Wilderness