Cornelius Smelt (August 1748 – 28 November 1832) was an administrator who served as Lieutenant Governor of the Isle of Man from 1805 until his death in 1832, the longest governorship in the history of the Island. An officer in the British Army, he served first with the 14th Regiment of Foot and then the 35th (Royal Sussex) Regiment of Foot, acting as Deputy Governor of Southsea Castle in the late 18th century. His governorship of the Isle of Man is remembered as one in which he displayed great moral courage in difficult circumstances. His wisdom and fortitude in the long period when the House of Keys and the Duke of Atholl fought their historic political battles were also evident. Upon his death, a memorial was erected in Castletown in the Isle of Man.