Father John B. McMahon, Assigned to the Mission at Eastport, Maine, shortly after his arrival from Ireland in 1840

Father John B. McMahon (abt 1805-), ordained in Ireland, arrived in Boston in 1840 and was assigned to the mission at Eastport, Maine, from about 1841-1843, where he also provided medical services, at no cost, to his parishioners.

Because Father McMahon spoke Gaelic, he was much in demand to hear confession from the newly arrived immigrants from  Ireland and was recalled to Boston by Bishop John Fitzpatrick.

http://www.thebostonpilot.com/opinion/article.asp?ID=193962

Another source mentions that Father McMahon, or another Father McMahon was in Eastport in 1838 [the article says 1828 but 1838 seems more fitting] when Brevet-Brigadier General Brady, colonel of the 2 regiment of Infantry of the U.S. requested the presence of Father McMahon of Eastport to administer the Sacred Sacraments to the soldiers at Hancock barracks in Houlton.

Father John B. McMahon is mentioned several times in The Catholic Church in Maine, written by William Leo Lucey and published in 1957 - particularly on pages 78 and 79

If you have information on Father John B. McMahon, please leave a comment for the benefit of others.

Rathlin Island, Northern Ireland

Many folks downeast have ancestors who came to Maine and the Maritimes from Rathlin Island, off the coast of Northern Island. If you have more information, please leave a comment. 

 Rathlin Island was featured on CNN on January 13, 2023 as one of "the best islands in Europe for getting away from almost everyone" - has about 150 year round residents now. 

https://www.cnn.com/travel/article/underrated-european-islands/index.html?gallery=8