Stillwater is a city in Washington County, Minnesota, directly across the St. Croix River from the state of Wisconsin. The population was 18,225 at the 2010 census. It is the county seat of Washington County. Stillwater is part of the Twin Cities Metro Area.
According to the United States Census Bureau, the city has a total area of 7.3 square miles (18.9 km²), of which, 6.5 square miles (16.8 km²) of it is land and 0.8 square miles (2.1 km²) of it (11.37%) is water. State Highways 36, 95, and 96 are three of the main routes in the community.
Stillwater receives an average annual snowfall of 42 inches (1,100 mm). Average annual rainfall is 24 in (610 mm). Each year has an average of 14 days above 90 °F (32 °C).