The Orange County Historical Museum was founded by the Hillsborough Garden Club in 1957. In May 2007, the Orange County Historical Museum merged with the Hillsborough Historical Society to form the Historical Foundation of Hillsborough and Orange County, a 501(c)(3) nonprofit organization.
The corner of lot 98 in downtown Hillsborough was originally the location of the Session House for the adjacent Presbyterian Church. In 1910, it was converted into the town's public library. The current building was constructed in 1934 in conjunction with New Deal programs.