Place
- MIssouri1
- Mariana Islands1
- Mexico1
- Mid Atlantic States1
- Middle East1
- Monhegan Island (Me.)1
- Montauk (N.Y.)1
- Monterey Bay (Calif.)1
- Nantucket (Mass.)1
- Nantucket Harbor (Mass.)1
- New York1
- New York State Canal System (N.Y.)1
- Northeastern states1
- Pajaro River Valley (Calif.)1
- Passamaquoddy Bay (N.B. and Me.)1
- Pawtuxet River (R.I.)1
- Pettaquamscutt River (R.I.)1
- Piscataqua River (N.H. and Me.)1
- Plymoth (Mass.)1
- Plymouth Bay (Mass.)1