[7] Deciding to enter the priesthood, Heffron began his studies under the Benedictines at St. John's College in Collegeville, MN, graduating in 1878.

[8] He then continued his studies at the Grand Séminaire de Montréal and received the degree of Doctor of Divinity in 1883.

[8] Archbishop John Ireland sent him to further his studies in Rome, where he earned doctorates in theology and canon law from the college at Santa Maria sopra Minerva in 1889.

[3] When Heffron became bishop in 1910, the Diocese of Winona contained a Catholic population of over 49,000 with 91 priests, 116 churches, and 29 parochial schools with 4,700 students.

[2] On August 27, 1915, Heffron was shot twice while celebrating private mass by Laurence M. Lesches, a diocesan priest.