Effin is a townland and civil parish in County Limerick, Ireland. It is on the R515 road, midway between Kilmallock and Charleville. The population of the parish is about 1,000. Effin is partly in the barony of Costlea, but chiefly in that of Coshma. The parish lies in the heart of the Golden Vale, Munster's rich dairyland, and intensive dairying is practised there. Ballyhoura Mountains which separate County Limerick from County Cork, are at the southern end of the parish.