South Lebanon is a village located in Union and Hamilton Townships in central Warren County in the southwestern part of the U.S. state of Ohio. The population was 4,115 at the 2010 census.
The first settlement at South Lebanon was made in the 1790s. The village was originally called "Deerfield" because it was the chief settlement of Deerfield Township, Warren County, Ohio, but renamed because of its proximity to the county seat of Lebanon. The new name of "South Lebanon" was adopted when the railroad was built through the neighborhood. A post office was established under the name Deerfield Village in 1828, and the name of the post office was changed to South Lebanon in 1871.
South Lebanon is located at 39°22′14″N 84°12′58″W (39.370581, -84.216084).
According to the United States Census Bureau, the village has a total area of 2.68 square miles (6.94 km2), of which 2.65 square miles (6.86 km2) is land and 0.03 square miles (0.08 km2) is water.
Most of the village is in the Kings Local School District, but parts are in the Little Miami Local and Lebanon City School Districts. It is entirely in the South Lebanon telephone exchange.
As of the census of 2010, there were 4,115 people, 1,533 households, and 1,118 families living in the village. The population density was 1,552.8 inhabitants per square mile (599.5/km2). There were 1,641 housing units at an average density of 619.2 per square mile (239.1/km2).