Watertown is a city in and the county seat of Codington County, South Dakota, United States. The population was 20,237 at the 2000 census. It is also the principal city of the Watertown Micropolitan Statistical Area, which includes all of Codington and Hamlin counties. Gary Williams is the current Mayor. Watertown has one public high school, Watertown High School, and one private boarding school, Great Plains Lutheran High School. 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 also is home to the Bramble Park Zoo. The Watertown Public Opinion is a six-day daily newspaper published in Watertown.