Watertown is a city in and the county seat of Codington County, South Dakota, United States. Watertown is home to the Redlin Art Center which houses many of the original art works produced by Terry Redlin, one of America's most popular wildlife artists. Watertown is located between Pelican Lake and Lake Kampeska, from which Redlin derived inspiration for his artwork. The population was 21,482 at the 2010 census, making Watertown the fifth largest city in South Dakota.