Vernon is a town in Vernon Township, Jennings County, Indiana, United States. As of the 2010 census, the town population was 318. As the county seat of Jennings County, it is the smallest town with that designation in the state of Indiana. It is nearly surrounded by the Muscatatuck River. Vernon has the only elected mayor of a town in the state of Indiana and the only elected town marshal. As of 2010, Dan Wright is Mayor and Tom Franks is the Marshal.
The town is on the National Register of Historic Places and is the host of many firsts in the state.
It was also the home of Indiana's fourth state park, now called Muscatatuck County Park.