The River Main or Maine () is a river in Northern Ireland, flowing through County Antrim.
Former prime minister of Northern Ireland Terence O'Neill took the title "Baron O'Neill of the Maine" when he was made a life peer.
The River Maine rises in the Glens of Antrim, flowing through Cullybackey and Randalstown before entering Lough Neagh.
The River Maine is a noted salmon and trout fishery.