There are 22 US Post Offices in Kitsap County serving a total of 194,056 residents equating to 8,821 residents per post office. It's estimated that approximately 309,735 packages are handled across the 22 county post offices annually. Kitsap County is located in the U.S. state of Washington. As of the 2010 census, its population was 251,133. Its county seat is Port Orchard, and its largest city is Bremerton. The county was formed out of King County, Washington, and Jefferson County, Washington on January 16, 1857 and is named for Chief Kitsap of the Suquamish Tribe. Originally named Slaughter County, it was soon renamed. Kitsap County comprises the Bremerton-Silverdale, WA Metropolitan Statistical Area, which is also included in the Seattle-Tacoma, WA Combined Statistical Area. The United States Navy is the largest employer in the county, with installations at Puget Sound Naval Shipyard, Naval Undersea Warfare Center Keyport, and Naval Base Kitsap (which comprises former NSB Bangor, and NS Bremerton). Kitsap County is connected to the eastern shore of Puget Sound by Washington State Ferries routes, including the Seattle-Bremerton Ferry, Southworth to West Seattle via Vashon Island, Bainbridge Island to Downtown Seattle, and from Kingston to Edmonds, Washington."