There are 13 US Post Offices in Thurston County serving a total of 228,480 residents equating to 17,575 residents per post office. It's estimated that approximately 364,680 packages are handled across the 13 county post offices annually. Thurston County is a county located in the U.S. state of Washington. As of the 2010 census, its population was 252,264. The county seat and largest city is Olympia, the state capital. Thurston County was created out of Lewis County by the government of Oregon Territory on January 12, 1852. At that time, it covered all of the Puget Sound region and the Olympic Peninsula. On December 22 of the same year, Pierce, King, Island, and Jefferson counties were split off from Thurston County. It is named after Samuel R. Thurston, the Oregon Territory's first delegate to Congress. Thurston County comprises the Olympia-Tumwater, WA Metropolitan Statistical Area and is included in the Seattle-Tacoma, WA Combined Statistical Area."