Port Orchard is a city in and the county seat of Kitsap County, Washington, United States. It is located 13 miles due west of West Seattle and is connected to Seattle and Vashon Island via the Washington State Ferries run to Southworth. It is named after Port Orchard, the strait that separates Bainbridge Island from the Kitsap Peninsula.

Port Orchard is located in south-central Kitsap County at 47°31′54″N 122°38′18″W , on the south side of Sinclair Inlet, an arm of the Port Orchard strait connecting to Puget Sound. The city is bordered to the north across Sinclair Inlet by the city of Bremerton.

According to the United States Census Bureau, the city has a total area of 11.21 square miles, of which 9.64 square miles are land and 1.57 square miles , or 15.65%, are water.

The town that was to become Port Orchard was originally platted in 1886 by Frederick Stevens, who named the new location after his father, Sidney. The town of Sidney was incorporated September 15, 1890, and was the first in Kitsap County to be both platted and incorporated. Shortly thereafter, the U.S. Navy sought a suitable location for another installation on the West Coast, and found it with the assistance of Sidney's residents in Orchard Bay (this installation would later become the Puget Sound Naval Shipyard in Bremerton).

The county seat was originally in Port Madison, but moved to Sidney after a popular vote in 1892. In December of that same year, the residents of Sidney petitioned both the state legislature and the Post Office Department to rename the city "Port Orchard"