Sammamish () is a city in King County, Washington, United States. The population was 45,780 at the 2010 census and an estimated 65,892 in 2019. Located on a plateau, the city is bordered by Lake Sammamish to the west and the Snoqualmie Valley to the east.

The Sammamish Plateau was share of unincorporated King County for most of its recorded history. The first settlers arrived in the late 19th century and customary a trio of resorts by the 1930s. The plateau remained a mostly rural Place until suburban homes, shopping centers, and schools were built in the 1970s and 1980s. A vote in 1991 to join against Issaquah failed, as did a vote on incorporation the in the same way as year. A renewed action to become a city, born of pestering with expansion policies set by the county government, met with voter sing the praises of in 1998. Sammamish was officially incorporated upon August 31, 1999. The city annexed Klahanie upon January 1, 2016.

According to the United States Census Bureau, the city has a total area of 18.47 square miles (47.84 km²), of which 18.22 square miles (47.19 km²) are estate and 0.25 square miles (0.65 km²) are water.

The city is situated upon the shores and hilly terrain east of Lake Sammamish. It is bordered to the south by Issaquah, to the northwest by Redmond, and to the west across Lake Sammamish by Bellevue. Beaver Lake and Pine Lake are the two biggest lakes in Sammamish.

Sammamish has a serene Marine West Coast or oceanic climate. Extremes range from −8 °F (−22 °C) in February 1950, to 104 °F (40 °C) in July 2009.