Storm Lake is a city in and the county seat of Buena Vista County, Iowa, United States. The population was 11,269 in the 2020 census, an increase from 10,076 in the 2000 census. Located along the northern shore of the Storm Lake reservoir, the city is home to Buena Vista University, King's Pointe Waterpark Resort, the Living Heritage Tree Museum, and the Santa's Castle holiday attraction. It is the principal city of the Storm Lake micropolitan area.