Diocese of Chatham, New Brunswick This former Roman Catholic Diocese once covered the entire north of the Province of New Brunswick. It dates from 1860.

In its early years, Irish clergy dominated its affairs, though there was a French Catholic majority population in more northerly Restigouche and Gloucester Counties. Northumberland County, where Chatham was located, was predominantly Irish and Scottish Catholic. Over time, however, the tendency of the Irish to prefer an urban life and move to Boston and other parts of the USA, reduced the English speaking Catholic populations, especially in the northern counties.

The first bishop was The Most Reverend James Rogers who retired in 1902, a well respected and portly Irishman who did much to build the Catholic Church in the Diocese. Religious orders were brought in, schools and hospitals built and vocations harvested. A fine cathedral, now St. Michael's Basilica was constructed, with a matching Bishop's Palace which housed the diocesan administration as well as the bishop. Colleges were opened in Chatham for the English (now St. Thomas University (New Brunswick)) and Bathurst (for the French). Bishop Thomas Barry continued Bishop Roger's work from 1902 to 1920.

The next appointment was a French speaker. By this time the French were in a majority in the diocese and Bishop Patrice Chiasson decided to move his headquarters to Bathurst, a majority French speaking area. The move was complete in 1938.

Chatham was left with a large and beautiful church, larger than most of the cathedrals of western Canada.