Public Sites
| State | County | Name |
|---|---|---|
| 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 |
| Indiana | Scott | Marshfield |
| Iowa | Cherokee | Martin Area County Park |
| Iowa | Franklin | Martin Marietta Dows Quarry |
| Iowa | Linn | Martin Sports Complex |
| Texas | Galveston | Mary Edna Crawford Bird Sanctuary |
| Michigan | Keweenaw | Mary Macdonald Preserve at Horseshoe |
| Iowa | Mahaska | Maskunky Marsh |
| Iowa | Cerro Gordo | Mason City |
| Iowa | Dubuque | Massey Marina and Park |
| Iowa | Hamilton | Masterson Marsh |
| Iowa | Linn | Matsell Bridge Natural Area |
| Iowa | Linn | Matus Fen |
| Iowa | Story | Max Daley Pathway |
| Iowa | Osceola | May City Wildlife Management Area |