San Juan County
There are 8 US Post Offices in San Juan County serving a total of 15,639 residents equating to 1,955 residents per post office. It's estimated that approximately 24,962 packages are handled across the 8 county post offices annually. San Juan County is a county located in the Salish Sea in the far northwestern corner of the U.S. state of Washington. As of the 2010 census, its population was 15,769. The county seat and only incorporated city is Friday Harbor, located 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 G\u00fcemes, 2nd Count of Revillagigedo, the Viceroy of New Spain. It is the only county in Washington not to have state highways."