Iowa - Area of significance: Agriculture
| Armour Creameries Poultry House |
| Audubon County Home Historic District |
| Broad View Ranch Historic District |
| Brooks Round Barn |
| Bruce Goldfish Fisheries |
| Brugjeld-Peterson Family Farmstead District |
| Budd, Prof, J.L., Sarah M., and Etta Budd, House |
| Buresh Farm |
| Byal Orchard Historic District |
| Carstens Farmstead |
| Catalpa |
| Cedar Falls Downtown Historic District |
| Clark Round Barn |
| Coffin, Lorenzo S., Burial Plot |
| Dobbin Round Barn |
| Dow House |
| Duncan-Duitsman Farm Historic District |
| Dunham, Z. T., Pioneer Stock Farm |
| Dyas Hexagonal Barn |
| Eckle Round Barn |
| Evergreen Ridge Stock Farm Historic District |
| Faeth Farmstead and Orchard District |
| Farm Creek Historic District |
| Flynn Farm, Mansion, and Barn |
| Fobes Octagon Barn |
| Four Mounds Estate Historic District |
| Frantz Round Barn |
| Garst, Roswell and Elizabeth, Farmstead Historic District |
| Grimes Octagon Barn |
| Haner, William, Polygonal Barn |
| Hansen, Andrew P., Farmstead |
| Holtkamp Round Barn |
| Home of Marshall's Horseradish |
| Homestead Building |
| Hulme, Samuel and Sarah, House |
| Iowa State Fair and Exposition Grounds Historic District |
| Jacobson Farm |
| Johnson County Poor Farm and Asylum Historic District |
| Jones Creek Watershed Historic District |
| Kenny Farmstead Archeological District |
| Kinney Octagon Barn |
| Klinsky Farmstead Historic District |
| Knapp-Wilson House |
| Lange, August H. J. and Justena, Farmstead Historic District |
| Leet, William A., and Frederick Hassler Farmstead District |
| Lenox Round Barn |
| Lewelling, Henderson, House |
| Lewis, Judge W.H. and Emma, Historic District |
| Louden Machinery Company |
| Luedtke, August and Vera, Barn |
| Luther College Farm |
| Masonic Temple |
| McCollister, James, Farmstead |
| McCoy Polygonal Barn |
| McGreer, John, Barn and Crib |
| McKenzie, Erza, Round Barn |
| McQuilkin, James Greer, Round Barn |
| Meier, Fred W., Round Barn |
| Meyers Farmstead Historic District |
| Miller Round Barn |
| Mines of Spain Area Rural Community Archeological District |
| Minor, Josias L. and Elizabeth A., Farmstead District |
| Motor Mill Historic District |
| Muscatine County Home Dairy Barn |
| "Nebergall ""Knoll Crest"" Round Barn" |
| Nelson Round Barn |
| Newens Sanitary Dairy Historic District |
| Notbohm Mill Archaeological District |
| Nus, August, Polygonal Barn |
| Oakland, William, Round Barn |
| Octagon Barn, Otter Township |
| Octagon Barn, Richland Township |
| Octagon Round Barn, Indian Creek Township |
| Painter-Bernatz Mill |
| Plagmann Round Barn |
| Pleasant View Stock Farm Historic District |
| Poldberg, Chris, Farmstead |
| Polled Hereford Breed Origin Site |
| Polygonal Barn, Lincoln Township |
| Polygonal Barn, New Oregon Township |
| Polygonal Barn, Van Buren Township |
| Poplar Rural District |
| Potter's, E. G., Jasper Flour Mill |
| Reburn, Thomas, Polygonal Barn |
| Reynolds, Charles B., Round Barn |
| Roberts Octagon Barn |
| Ross Grain Elevator |
| Round Barn, Bruce Township Section 3 |
| Round Barn, Buckingham Township |
| Round Barn, Cooper Township |
| Round Barn, Dubuque Township |
| Round Barn, Millville Township |
| Round Barn, Norway Township |
| Round Barn, Pilot Grove Township |
| Round Barn, Washington Township |
| Round Barn, Washington Township |
| Rownd, C. A., Round Barn |
| Schmidt, Louis C. and Amelia L., House |
| Secrest Octagon Barn |
| Seerley, William and Mary (Messersmith) Barn and Milkhouse-Smokehouse |
Data from United States Park Service and Wikidata
