M
- Mabestown Stream, County Dublin
- Magazine Stream, County Dublin
- Maigue
- Maine*
- Mareen's Brook, County Dublin
- Mayne River, County Dublin
- Mill Stream, County Dublin
- Milverton Stream, County Dublin
- Monkstown Stream, County Dublin
- Mourne Beg*
- Mourne*
- River Moy, County Mayo
- Moyola*
- Muckross Stream, County Dublin
- Mulkear River, County Limerick
- Munkin River, County Mayo
Read more about this topic: Rivers Of Northern Ireland