Cornelius Denvir (1791–1866) was an Irish Roman Catholic prelate, mathematician, natural philosopher and former Lord Bishop of Down and Connor. He is noted for ministering in Belfast amidst growing sectarian tension, taking a moderate and non-confrontational stance, to the annoyance of his pro-Catholic followers. He was also a professor at Maynooth College as well as Down and Connor Diocesan College, and was active in the local scientific community.