Public Sites
| State | County | Name |
|---|---|---|
| Iowa | Shelby | Mantero Park |
| Iowa | Cherokee | Maple River @ 600th Street |
| Iowa | Jackson | Maquoketa |
| Iowa | Jackson | Maquoketa Caves State Park |
| Iowa | Clayton | Maquoketa River |
| Iowa | Dubuque | Maquoketa River @ Hwy 136 |
| Iowa | Fayette | Maquoketa River Wildlife Area |
| Iowa | Buena Vista | Marathon |
| Iowa | Dickinson | Marble Lake State Game Management Area |
| Iowa | Iowa | Marengo |
| Iowa | Polk | Margo Frankel Woods State Park |
| Iowa | Marshall | Marietta Sand Prairie State Preserve |
| Iowa | Marion | Marion County |
| Iowa | Marion | Marion County Park |
| West Virginia | Marion | Marion County, WV |
| Iowa | Linn | Marion YMCA |
| Iowa | Jasper | Mariposa County Park |
| Iowa | Mitchell | Markhams Pond |
| Iowa | Polk | Marquisville |
| Iowa | Washington | Marr Park |
| Iowa | Dickinson | Marsh @ Parks Marina |
| Iowa | Benton | Marsh at Vinton Airport S. of E-W runway |
| Iowa | Jones | Marsh, 3.5 miles west of Onslow |
| Iowa | Marshall | Marshall County |
| Iowa | Marshall | Marshalltown |