Havana is a city in Mason County, Illinois, United States. The population was 3,577 at the 2000 census, and 3,260 at a 2009 estimate. It is the county seat of Mason County.
Havana is located on the Illinois River at 40°17′49″N 90°3′36″W / 40.29694°N 90.06°W / 40.29694; -90.06 (40.297067, -90.060004). It is located near the Chautauqua National Wildlife Refuge, and a short distance from Bath, Illinois. Havana was notorious as a gambling river town, and it is reported that names such as Al Capone would hunt, fish, and gamble in the local clubs.
There were 1,467 households out of which 28.9% had children under the age of 18 living with them, 49.8% were married couples living together, 12.5% had a female householder with no husband present, and 33.1% were non-families. 29.6% of all households were made up of individuals and 17.2% had someone living alone who was 65 years of age or older. The average household size was 2.35 and the average family size was 2.88.