Lake Mills is a city in Winnebago County, Iowa, United States. The population was 2,140 at the 2000 census. Lake Mills is the home of Terry Edward Branstad (born November 17, 1946) a four-term Republican Governor of Iowa, who served from 1983 to 1999, and the birthplace of Pulitzer Prize winning author Wallace Stegner. Lake Mills does not have a lake within city limits.