Monasterevin, sometimes Monasterevan, is a town in County Kildare, Ireland. It lies on the River Barrow and the Barrowline, a canal branch of the Grand Canal. In the 20 years between the 2002 and 2022 censuses, the population more than doubled, from 2,583 to 5,307 inhabitants. The town is in a townland and civil parish of the same name.