John J. McMahon

John Joseph McMahon (September 27, 1875 – December 31, 1932) was an American prelate of the Roman Catholic Church. He served as Bishop of Trenton from 1928 until his death in 1932.

John McMahon was born in Hinsdale, New York, and graduated from Union High School in 1893. He then attended St. Bonaventure's College Allegany, from where he obtained a Bachelor of Arts degree, and completed his theological studies at the Pontifical Urbaniana University in Rome. He was ordained to the priesthood on May 20, 1900. Upon returning to New York, he served as a curate in Jamestown and Buffalo before becoming pastor of Newfane. He also served as assistant superintendent of diocesan schools and director of the Holy Name Society.

On March 2, 1928, McMahon was appointed the fourth Bishop of Trenton, New Jersey, by Pope Pius XI. He received his episcopal consecration on the following April 26 from Bishop William Turner, with Bishops Thomas Walsh and Edmund Gibbons serving as co-consecrators, at St. Joseph's Cathedral. He was installed at St. Mary's Cathedral in Trenton on May 10, 1928. After four years as bishop, McMahon died at age 57.