 US 79 was placed onto the existing state highway route upon its creation in 1935, and the two remained concurrent through the pre-1955 era.However, in the 1955 Louisiana Highway renumbering, unnecessary concurrencies between U.S. and state routes were eliminated, and the LA 9 designation was instead continued along a different pre-1955 state route north of Homer.On its south end, Route 12 was originally designated to form a "V" by heading southwest from Saline to Chestnut then turn sharply to the northwest to a terminus at Ashland.