The Old Governor's Mansion is a historic house museum of the Georgia College & State University (GCSU) at 120 South Clarke Street in Milledgeville, Georgia. Built in 1838, it is one of the finest examples of Greek Revival architecture in the American South, and was designated a National Historic Landmark for its architecture in 1973. It served as Georgia's executive mansion until 1868, and has from 1879 been a university property, serving for a time as its official president's residence.