| River Name | Wikipedia Link | Notes |
|---|---|---|
| Maine | https://en.wikipedia.org/wiki/River_Maine_(County_Kerry) | |
| Mulkear/Mulcair | https://en.wikipedia.org/wiki/Mulkear_River | Pronounced "mull-care |
| Mawddach | https://en.wikipedia.org/wiki/Afon_Mawddach | |
| Machrihanish | https://en.wikipedia.org/wiki/Machrihanish_Bay | |
| Minsmere | https://en.wikipedia.org/wiki/Minsmere_River | |
| Mondego | https://en.wikipedia.org/wiki/Mondego_River | |
| Moselle | https://en.wikipedia.org/wiki/Moselle | flows through Germany, Luxembourg, France, and the basin is in Belgium |
| Morava | https://en.wikipedia.org/wiki/Morava_(river) | |
| Medveditsa | https://en.wikipedia.org/wiki/Medveditsa_(Volga) |