Alma was a town in Lincoln Parish that was a railroad station on the Illinois Central Railroad in 1910. The town of Alma was named after the daughter of a Mr. Alexandria who routed the railroad through the Parish.
The first Post Office was named Alexton in 1900 and was later discontinued in 1919. Lewis A. Sims was named Postmaster.
So Alma became Alexton but the Post Office said that it was easily confused with Alexandria and required this town to be renamed once again
In 1919 Hilly was chosen which is a good description of the terrain. The Hilly Post Office was discontinued in 1957. Thomas A. Larance was the first Hilly Postmaster.