Mount Vernon was established in 1849 on land donated by Stephen and Rebecca Keith. When Franklin County was created in 1875, Mount Vernon was voted county seat. The first courthouse was a wooden building located northeast of the square.
In 1878 a brick courthouse was built on the square at a cost of $5,500. County commissioners ordered an election to decide the building of a new courthouse and jail in 1910, but the commissioners’ court rescinded that order and called for construction warrants to be issued without an election, and levied a property tax to pay for the new buildings. Citizens filed suit against the county, and in January 1911, the district court prevented construction from proceeding. An appellate court overturned the decision and within days of the landmark decision Franklin County Commissioners awarded a contract to L. R. Wright & Co. to construct this courthouse and adjacent jail. The buildings were completed in 1912 at a cost of $55,000.