Iowa - Criteria: A (event)
| St. Joseph's Roman Catholic Church and Cemetery Historic District |
| St. Katherine's Historic District |
| St. Luke's Hospital |
| St. Mary's Catholic Church Historic District |
| St. Mary's Catholic Church Historic District |
| St. Mary's Roman Catholic Church Complex |
| St. Michael's Church, Cemetery, Rectory and Ancient Order of Hibernians Hall |
| Stock Judging Pavilion |
| Stokes, Dr. Ella, House |
| St. Olaf Auditorium |
| Stoll Building Works |
| Stone Academy |
| Stone City Historic District |
| Stone House |
| Storm Lake Public Library |
| St. Patrick Church |
| St. Patrick's Church |
| St. Paul's English Lutheran Church |
| Stranahan, Prof. Edgar H. and Irene D., House |
| Stringtown House |
| Stuart, Dr. Richard and Paulina, House |
| Studebaker Corporation Branch Office Building |
| Sturdevant Southwest Historic District |
| Sumner High School |
| Sumner School |
| Surf Ballroom |
| Swedesburg Historic Commercial District |
| Swedish Baptist Church |
| Swedish Evangelical Lutheran Augustana Church |
| Swedish Evangelical Lutheran Church |
| Sylvan Theater Historic District |
| Syndicate Block |
| Tabor Antislavery Historic District |
| Tabor Congregational Church |
| Taft, Stephen Harris, House |
| Taft-West Warehouse |
| Tama County Jail |
| Tate Arms |
| Taylor School |
| Teachout Building |
| Terrace Park Historic District |
| Theodore Roosevelt High School |
| Third Street Bridge (FHWA No. 012250) |
| Thomsen Round Barn |
| Tidrick, Miller Richard and Mary Fisher, House |
| Todd House |
| Tonsfeldt Round Barn |
| Trappers Bay State Park Picnic Shelter |
| Trent-Beaver House |
| Trinity Episcopal Church |
| Troy Academy |
| Turner Hall |
| Tuttle, Thomas F. and Nancy, House |
| Tyden Farm No. 6 Farmstead Historic District |
| Ulysses Simpson Grant Elementary School |
| Union Bakery |
| Union Brewery |
| Union Cemetery Gardener's Cottage |
| Union Church |
| Union Electric Telephone & Telegraph |
| Union Savings Bank and Trust |
| Union Station and Burlington Freight House |
| Union Sunday School |
| United Presbyterian Church, Summerset |
| Upper Central Avenue Commercial Historic District |
| Upper Main Street Historic District |
| U.S. Post Office |
| U.S. Post Office and Courthouse |
| US Post Office-Iowa Falls |
| Vail, Mrs. Marian D.-Prof. Charles Noyes Kinney House |
| Valley Junction Commercial Historic District |
| Valley Junction-West Des Moines City Hall and Engine House |
| Valley Mills |
| Van Den Berg, Hendrik J. and Wilhelmina H., Cottage |
| Vander Wilt Farmstead Historic District |
| Van Loon, Dirk, House |
| Van Maren, Henry and Johanna, House-Diamond Filling Station |
| Vawter, J. G. and Elizabeth S., House |
| Veneman's Bungalow Court Historic District |
| Vermeer, Gary J. and Matilda, Farmstead |
| Vermilion Estate |
| Village of St. Donatus Historic District |
| Villisca National Guard Armory |
| Vinton Public Library |
| Wagner-Mozart Music Hall |
| Wahkonsa Hotel |
| Walnut Grove School |
| Walnut Tire and Battery Co.-Globe Publishing Company Building |
| Walsh Flats/Langworth Building |
| Wanata State Park Picnic Shelter |
| Wapsipinicon Mill |
| Warrior Hotel |
| Wartburg Teachers' Seminary |
| Washington and Elizabeth Miller Tract-Center-Soll Community Historic District |
| Washington Avenue Commercial Historic District |
| Washington Downtown Historic District |
| Washington Junior High School and Jefferson Grade School |
| Washington Park |
| Washington Prairie Methodist Church |
| Washington Residential Historic District |
Data from United States Park Service and Wikidata
