Iowa - Area of significance: Commerce
| Garner, J.W., Building |
| Germania-Miller/Standard Hotel |
| Gobble and Heer-Spurgeons Building |
| Grand Avenue Historic Commercial District |
| Grant Commercial Historic District |
| Greenfield Public Square Historic District |
| Grinnell Historic Commercial District |
| Grocers Wholesale Company Building |
| Gruwell and Crew General Store |
| Harbach, L. and Sons Furniture Warehouse and Factory Complex |
| Harper and McIntire Company Warehouse |
| Hawkeye Insurance Company Building |
| Hedge Block |
| Heritage Hill Historic District |
| Herring Hotel |
| Herring Motor Car Company Building |
| Hickman-Nietert-Odd Fellows Building |
| Highland Park Historic Business District at Euclid and Sixth Avenues |
| Hippee Building |
| Hobson Block |
| Home Oil Service Station |
| Hotel Burlington |
| Hotel Charitone |
| Hotel Chieftain |
| Hotel Hurst |
| Hotel Hurst Garage |
| Hotel Manning |
| Hotel Mississippi-RKO Orpheum Theater |
| Hotel Ottumwa |
| Hotel President |
| Hotel Rea |
| Hotel Russell-Lamson |
| Hotel Tipton |
| Howes Building |
| Hubbell Building |
| Hubbell Warehouse |
| Hughes-Irons Motor Company |
| Ijem Avenue Commercial Historic District |
| International Harvester Truck Sales and Service Station |
| Interstate Power Company Building |
| IOOF Building |
| Iowa City Downtown Historic District |
| Iowa Mutual Insurance Company Home Office |
| Iowana Hotel |
| Iowan's Hotel |
| Jefferson Square Commercial Historic District |
| Jones, G.W., Building |
| Kahl, Henry, House |
| Kerndt, G., & Brothers Office Block |
| Kimballton Commercial District |
| King Tower Historic District |
| Kirk, The |
| Kreinbring Phillips 66 Gas Station |
| Kuhnen, Nicholas J., House |
| Kurtz, Glenn and Nell, Lustron Home and Garage |
| Lagomarcino-Grupe Company |
| Lansing Main Street Historic District |
| Lattner Auditorium Building |
| LeClaire, Antoine, House |
| Le Mars Downtown Commercial Historic District |
| Lenox Hotel |
| Lewis Hotel |
| Lewis, Judge W.H. and Emma, Historic District |
| Lewis System Armored Car and Detective Service Building |
| Liberty Building |
| Lincoln-Fairview Historic District |
| Lincoln Hotel |
| Lisbon Main Street Historic District |
| Lock and Dam No. 11 Historic District |
| Lock and Dam No. 12 Historic District |
| Lock and Dam No. 14 Historic District |
| Lock and Dam No. 16 Historic District |
| Lock and Dam No. 19 Historic District |
| Lucas County Courthouse Square Historic District |
| Luther A. and Elinore T. Brewer House |
| Lyon Block |
| Mack-International Motor Truck Corporation Building |
| Manning Commercial Historic District |
| Manning Milwaukee Railroad Trestle |
| Manufacturing and Wholesale Historic District |
| Maquoketa Commercial Historic District |
| Marble Rock Bank |
| Marion Commercial Historic District |
| Marshalltown Downtown Historic District |
| Marsh-Place Building |
| Martin Hotel |
| Martin, T.S., and Company |
| Mason City Downtown Historic District |
| McCleery Calendar Factory |
| McCormick Harvesting Machine Company Building |
| McGregor Commercial Historic District |
| McKee Button Company |
| McKibben, S. M., House |
| McWaid, Job A. and Rebecca E., House |
| Meek's Flour Mill |
| Mentzer, Joseph P., House |
| Merrero Building |
| Miller, F. H., House |
| Mitchell-Maskrey Mill |
| Moeszinger-Marquis Hardware Co. |
Data from United States Park Service and Wikidata
