Havana is a city in Mason County, Illinois, United States. The population was 3,301 at the 2010 census, and 3,040 at a 2018 estimate. It is the county seat of Mason County.
The city was named after Havana, the capital of Cuba.
Havana is located on the Illinois River at 40°17′49″N 90°3′36″W (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. According to the 2010 census, Havana has a total area of 2.905 square miles (7.52 km2), of which 2.74 square miles (7.10 km2) (or 94.32%) is land and 0.165 square miles (0.43 km2) (or 5.68%) is water.
According to the United States Census Bureau, the city has a total area of 2.8 square miles (7.2 km2), of which, 2.6 square miles (6.8 km2) of it is land and 0.2 square miles (0.4 km2) of it (5.40%) is water.
As of the census of 2000, there were 3,577 people, 1,467 households, and 981 families residing in the city. The population density was 1,361.0 people per square mile (525.1/km2). There were 1,587 housing units at an average density of 603.8/sq mi (233.0/km2). The racial makeup of the city was 98.49% White, 0.14% African American, 0.14% Native American, 0.53% Asian, 0.06% from other races, and 0.64% from two or more races.