Duvall is a city in King County, Washington, United States, located on SR 203 halfway between Monroe and Carnation. The population was 8,034 at the 2020 census.

State Route 203 (SR 203) is a state highway in the U.S. state of Washington that traverses part of King and Snohomish counties. It runs north–south for 24 miles (39 km) through the Snoqualmie Valley, connecting Fall City, Carnation, Duvall, and Monroe. The highway terminates to the south at a roundabout with SR 202 near Fall City and to the north at a junction with U.S. Route 2 (US 2) in Monroe.