Lebanon is a town on the southern border of Madison County, New York state, United States. The population was 1,332 at the 2010 census. The town is believed to be named after Lebanon, Connecticut. Settlement of Lebanon began circa 1791. The town was established in 1807, from part of the Town of Hamilton. Many of the early inhabitants were from Conn…Lebanon is a town on the southern border of Madison County, New York state, United States. The population was 1,332 at the 2010 census. The town is believed to be named after Lebanon, Connecticut. Settlement of Lebanon began circa 1791. The town was established in 1807, from part of the Town of Hamilton. Many of the early inhabitants were from Connecticut.