Watertown is a city in and the county seat of Codington County, South Dakota, United States. The population was 21,482 at the 2010 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 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.