Iowa - Criteria: B (person)
| St. Katherine's Historic District |
| St. Mary's Catholic Church Historic District |
| Stone City Historic District |
| Stratton House |
| Sturdevant Southwest Historic District |
| Suiter, Jacob, House |
| Suiter, John H., House |
| Suiter, William, House |
| Taft, Stephen Harris, House |
| Tate Arms |
| Teachout Building |
| Temple, Marcellus Luther and Julia Protzman, House |
| Terrace Hill |
| Thedinga, J. H., House |
| Tromley, George, Jr., House |
| Tromley, George, Sr., House |
| Tyden Farm No. 6 Farmstead Historic District |
| Van Sant, Samuel, House |
| Vermeer, Gary J. and Matilda, Farmstead |
| Vincent House |
| Voorhees, John K., House |
| Wallace, Henry C., House |
| Wallace, Henry, House |
| Wasson, Dr. Jesse, Building |
| Weaver, James B., House |
| Wells-Stubbs House |
| Wetherby, Isaac A., House |
| Wild, Daniel and Margaret, House |
| Willow-Bluff-3rd Street Historic District |
| Wilson, Anson, House |
| Wilson Building |
| Wilson, John, House |
| Wilson, Paton and Hannah, House |
| Wilson, US Senator James F., House |
| Winterset Courthouse Square Commercial Historic District |
| Wishard, Henry, House |
| Wood, William Kennison, House |
| Zitterell, William J. and Hattie J., House |
Data from United States Park Service and Wikidata
