Watertown is a city in Dodge and Jefferson counties in the U.S. state of Wisconsin. Most of the city's population is in Jefferson County. Division Street, several blocks north of downtown, marks the county line. The population of Watertown was 21,598 at the 2000 census. Its 2007 estimated population was 23,301.
Watertown is the largest city in the Watertown-Fort Atkinson micropolitan area, which also includes Johnson Creek and Jefferson. The 2005 estimated population of the micropolitan area was 79,328. Watertown's estimated population in 2008 was 23,165.
Watertown was first settled by Timothy Johnson, who built a cabin on the west side of the Rock River in 1836. A park on the west side of the city is named in his honor. The area was settled to utilize the power of the Rock River, which falls 20 feet (6.1 m) in two miles (two 10-foot (3.0 m) dams). In contrast, the Rock River falls only 34 feet (10 m) 58 miles (93 km) upstream from Watertown. The water power was first used for sawmills, and later prompted the construction of two hydroelectric dams, one downtown (where the river flows south) and one on the eastern edge of the city (where the river flows north).