Henry Downes was an eighteenth-century Irish Anglican bishop.
He was nominated Bishop of Killala and Achonry on 24 January 1717 and consecrated on 12 May that year. In 1720 he was translated to Elphin, being nominated on 1 May and appointed by letters patent on 12 May 1720. In 1724 he was nominated on 17 March to be the Bishop of Derry and appointed by letters patent on 9 April 1724. Finally on 11 January 1727 he was nominated Bishop of Derry and appointed by letters patent on 8 February 1727. He died in office on 14 January 1735.