Sullivan is located in Illinois. Sullivan, Illinois has a population of 4,347. Sullivan is less family-centric than the surrounding county with 24% households with children. The county percentage for households with children is 29%.
The median household income in Sullivan, Illinois is $59,693. The median household income for the surrounding county is $62,913 compared to the national median of $66,222. The median age of people living in Sullivan is 41.7 years.
The average high temperature in July is 86.9 degrees, with an average low temperature in January of 18.9 degrees. The annual precipitation is 39.14.