First Mass

July 10, 1840

Photos

Documentation

• Gilbert J. Garraghan, S.J., "Catholic First Things in the United States," Mid-America: An Historical Review, vol. 21 (1939)

Notes

Per Gilbert J. Garraghan, S.J., Fr. Pierre-Jean De Smet, who by his own account said Mass every Sunday and feast day during his 1840 journey to the Rocky Mountains, very probably said his first Mass in Idaho around July 12, 1840, shortly after crossing from Wyoming. Big Sky Words (https://www.bigskywords.com/montana-blog/father-pierre-jean-de-smet-heeds-the-call) independently confirms De Smet reached Pierre's Hole (Teton Basin) around this date, where he baptized roughly 350 Salish and Pend d'Oreille people. No source independently confirms a Mass specifically on this date — Garraghan treats it as probable rather than certain, and rates a separate, later Mass (July 23, at Henry's Lake, submitted separately) as the first of explicit record in the state. Wikipedia's article on Pierre-Jean De Smet confirms his 1840 journey generally. Note the Idaho Marker says July 10, not 12, going with that as the official date.