Friday Harbor is a town in San Juan County, Washington, United States. The population was 2,162 at 2010 census. Located on San Juan Island, Friday Harbor is the major commercial center of the San Juan Islands archipelago and is the county seat of San Juan County.
In 1845 the Hudson's Bay Company laid claim to San Juan Island. In 1850 they built a salmon curing station. A few years later they started a sheep farm.
The town's name originates from Joseph Poalie Friday, a native Hawaiian. Friday worked at the Pugets Sound Agricultural Company's Fort Cowlitz, from 1841 to 1859–60 and later moved north to San Juan Island, raising and herding sheep around the harbor.
After the peaceful settlement obtained following the Pig War, the San Juan Islands became a separate county in 1873. Friday Harbor was named the county seat.
Friday Harbor was officially incorporated on February 10, 1909. It remains the only incorporated town in the San Juan Is