There are 24 US Post Offices in Snohomish County serving a total of 535,075 residents equating to 22,295 residents per post office. It's estimated that approximately 854,039 packages are handled across the 24 county post offices annually. Snohomish County /sno\u028a\u02c8ho\u028am\u1d7b\u0283/ is a county located in the U.S. state of Washington. As of the 2015 census, the population was 772,501, making it the third-most populous county in Washington. The county seat and largest city is Everett. The county was created out of Island County on January 14, 1861 and is named for the Snohomish tribe. Snohomish County is included in the Seattle-Tacoma-Bellevue, WA Metropolitan Statistical Area."