The original courthouse was built in 1842 and burned down in 1859. A second one was built in it's place in 1871.The second courthouse was demolished in 1957 after the construction of the current building.
The Courthouse Hill Historic District rises above the city of Janesville and the east side of the Rock River on a steep bluff. This residential neighborhood contains outstanding examples of the architectural styles associated with Janesville's growth and development from settlement to 1940. Many of the Courthouse Hill's early residents were influential in commerce, industry and legal affairs. This district contains 30 blocks and 219 properties which were listed in the National register of Historic Places in 1986.