Iowa - Constructed - 1920–1929
| Abraham Lincoln High School |
| Apperson-Iowa Motor Car Company Building |
| Armour Creameries Poultry House |
| Benson Block |
| Berry, Dr. William E. and Ethel Rosenberger, House |
| Conant's Cabin and Park |
| Davenport Bank and Trust (Boundary Increase) |
| Economy Advertising Company |
| Elmwood, The- The Oaks-The Birches |
| Farmers and Merchants Savings Bank |
| Fort Madison Bridge |
| Fryer, O.F. and Lulu E., House |
| Harper and McIntire Company Warehouse |
| Hotel Roosevelt |
| Iowa Malleable Iron Company |
| Jenkins, Dr. George A., House |
| Louden, R.R., and Antoinette, House |
| Mack-International Motor Truck Corporation Building |
| Maquoketa Caves State Park Historic District |
| Mary Elizabeth Day Nursery |
| McCleery Calendar Factory |
| Muscatine County Home Dairy Barn |
| Pyle, Glenn O. and Lucy O., House |
| Saint John's Roman Catholic Church |
| Shay, Lee, Farmhouse |
| Shelby Consolidated School |
| Sigma Pi Fraternity House |
| Sioux City Public Library (Smith Villa Branch) |
| St. Mary’s Roman Catholic Church |
| Stranahan, Prof. Edgar H. and Irene D., House |
| Theodore Roosevelt High School |
| Walnut Tire and Battery Co.-Globe Publishing Company Building |
| Wapsipinicon State Park Historic District |
Data from United States Park Service and Wikidata
