The Diocese was established on 22 September 1844, under the name of the Diocese of Arichat, on territory split off from the Diocese of Halifax. Its cathedral was located on Cape Breton Island, in the port town of Arichat. On 23 August 1886, the diocese was renamed the Diocese of Antigonish, and its episcopal see moved to St. Ninian's Cathedral, on the Nova Scotia mainland in the town of Antigonish.
2009–2010 apostolic administration
On August 7, 2009, Bishop Raymond Lahey announced that the Diocese of Antigonish had reached a $15 million settlement in a class action lawsuit filed by 125 victims of sexual abuse by Hugh Vincent MacDonald and other diocese priests dating from 1950 to 2009. On September 26, 2009 Pope Benedict XVI accepted the resignation of Bishop Raymond Lahey, one day after a warrant was issued for his arrest by the Ottawa Police Service relating to child pornography charges. The bishop pleaded guilty to child pornography charges and was jailed. Archbishop Anthony Mancini of the Archdiocese of Halifax was named the Apostolic Administrator effective September 26, 2009, and remained in that position until the installation of Brian Dunn on January 25, 2010.
Extent
The Diocese of Antigonish covers 18,800 square kilometers, comprising the counties of Pictou, Antigonish, Guysborough, Inverness, Victoria, Richmond and Cape Breton. As of 2006, the diocese contained 123 parishes, 119 active diocesan priests, 8 religious priests, and 129,905 Catholics. It also has 290 women religious, 12 religious brothers and 1 permanent deacon. In 2012 in order to satisfy its legal obligations to pay out $15 million to the victims of sexual abuse, the diocese had to sell a large number of its lands and properties, liquidating the bank accounts of many of its churches, and borrowing $6.5 million from private lenders to make the payout. Until 2015, the Bishop of Antigonish served ex officio as Chancellor of St. Francis Xavier University.
Bishops
The following is a list of the bishops, all Roman Rite, and their terms of service: ; suffragan bishops of Arichat
William Fraser |William Fraser , previously titular Bishop of Tanis, Apostolic Vicar of Nova Scotia , Bishop of Diocese of Halifax
Raymond Lahey, previously Bishop of Saint George's ; later Lay state
Apostolic Administrator Anthony Mancini -, while Metropolitan Archbishop of Halifax
Brian Dunn, previously Titular Bishop of Munatiana and Auxiliary Bishop of Sault Sainte Marie ; appointed, 13 Apr 2019, Coadjutor Archbishop of Halifax-Yarmouth, Nova Scotia
Wayne Joseph Kirkpatrick, previously Titular Bishop of Aradi and Auxiliary Bishop of Toronto
; Other priests of this diocese who became bishops
Thomas Sears, appointed Prefect of Western Newfoundland in 1871
