Grundy County Illinois (Historic Districts) has 2 places on the National Register of Historic Places including 1 place of National significance. Significant places include Dresden Island Lock and Dam Historic District, Morris Downtown Commercial Historic District.
Some of the country's most noteable architects helped create the Grundy County places including Walter Mickle Smith and J.W. Royer. Prominent architectural styles found in Grundy Country are Early Commercial and Italianate.