Douglas County Illinois has 4 places on the National Register of Historic Places including 1 place of Statewide significance. Significant places include McCarty, John, Round Barn, Arcola Carnegie Public Library, Illinois Central Interlocking Tower, Streibich Blacksmith Shop.
Some of the country's most noteable architects helped create the Douglas County places including Horace Duncan, J.P. Morehead and Paul A. Moratz. Prominent architectural styles found in Douglas Country are Classical Revival and Late Victorian.