Patrick Bonaventure Geoghegan, O.F.M. (1805–1864) was a Roman Catholic clergyman who served firstly as Bishop of Adelaide, then briefly as Bishop of Goulburn, Australia.
Born in Dublin, Ireland, he was baptised on 17 March 1805. He was professed as a member of the Order of Friars Minor on 21 February 1830 as Friar Bonaventure, and ordained to the priesthood on 25 April 1835.
Geoghegan was sent to the British Colony of South Australia, where he was later appointed the Bishop of Adelaide by the Holy See on 15 April 1859, and consecrated on 8 September 1859. The principal consecrator was Archbishop John Bede Polding OSB of Sydney, and the principal co-consecrators were Archbishop James Alipius Goold of Melbourne, and Bishop Robert William Willson of Hobart.
He was translated to the newly formed Diocese of Goulburn, now the Roman Catholic Archdiocese of Canberra and Goulburn, on 10 March 1864, however, he died a few months later from throat cancer on 9 May 1864, aged 59, before he could take up his new post.