High Quality Content by WIKIPEDIA articles! 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. As of the 2000 census, the village population was 2,538, down from 2,696 in 1990. The village was originally called Deerfield because it was the chief settlement of Deerfield Township, Hamilton County, Ohio, but renamed because of its proximity to the county seat of Lebanon.