| Property | Address | City | Date Listed |
|---|---|---|---|
| Garretson Outlet Bridge | Co. Rd. K64 over Garretson Outlet Ditch | Whiting vicinity | 3/12/99 |
| Jones Creek Watershed Historic District | Between Little Sioux and Soldier Rivers SW of Moorhead | Moorhead | 12/23/1991 |
| Mann School No. 2 | Oak Avenue, 3.5 miles NW of Preparation Canyon State Park entrance | Moorehead vicinity | 1/16/2001 |
| Monona County Courthouse | Iowa Ave. | Onawa | 07/02/1981 |
| Onawa IOOF Opera House | 1023 Tenth Ave. | Onawa | 08/03/1990 |
| Onawa Public Library | Iowa Ave. and 7th Street | Onawa | 10/01/1979 |
| Round Barn | Cooper Township IA 141 | Mapleton | 06/30/1986 |
| Trinity Memorial Episcopal Church | 302 S. Seventh Street | Mapleton | 08/10/1990 |
| Whiting Newell A. House | 1106 Iowa Ave. | Onawa | 08/10/1990 |