The original three-story stone structure was built from stone on the Charles Willingham farm on the south side of the Colorado River. At a cost of $29,015 the construction process started on October 1, 1888, and was completed in October 1889. The three-story structure served county needs from 1889 to 1941. With the need for new space, a renovation was ordered and a two-story wing was added to each side of the courthouse. The interior was completely renovated and an elevator installed. Using stone from the same quarry used in 1888 the 1941 renovations and additions cost $65,000.
The Runnels County courthouse square is one of the largest in the state of Texas. and plays host to the statewide famous Ethnic Festival every year.