[5] On the night of March 31, 2023, Sullivan was struck by a large, powerful and deadly tornado as part of a much larger outbreak, causing catastrophic damage in the city and surrounding parts of the county.

At least 3 people were confirmed dead and several others injured, while at least 200 structures sustained some sort of damage.

[8] According to the 2010 census, Sullivan has a total area of 1.88 square miles (4.87 km2), all land.

There were 2,110 housing units at an average density of 1,122.3 per square mile (433.3/km2).

37.1% of all households were made up of individuals, and 18.1% had someone living alone who was 65 years of age or older.

There were 2,264 housing units at an average density of 1,181.8 per square mile (456.3/km2).

36.0% of all households were made up of individuals, and 19.9% had someone living alone who was 65 years of age or older.