Lebanon is a city in St. Clair County, Illinois, United States.

The population was 4,691 at the 2020 census It is a part of the Metro East region of the Greater St. Louis metropolitan area.

Lebanon is home to McKendree University, the oldest college in Illinois.

[3] As of the census[5] of 2010, there were 5,523 people, 1,275 households, and 804 families residing in the city.

28.5% of all households were made up of individuals, and 12.9% had someone living alone who was 65 years of age or older.