The Webster-Ashburton Treaty of 1842, which established the Maine-New Brunswick boundary along the St. John River, divided the Acadian settlements in the valley. Among the questions this posed for residents and for church officials was the location of the diocesan boundary: would it follow national, or ethnic lines? The ultimate resolution - the parishes south of the river were transferred to the Diocese of Portland - depended not only on established Roman Catholic practice in matters of changing national boundaries, but also upon the personalities involved, including the bishops of Portland and Saint John and the parishioners on both sides of the river in Madawaska.
Stevenson, Michael D., and Graeme S. Mount. "The Roman Catholic Diocesan Boundary and American Madawaska, 1842-1870." Maine History 32, 3 (1993): 174-189. https://digitalcommons.library.umaine.edu/mainehistoryjournal/vol32/iss3/3