First Mass

July 23, 1840

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 said "a Mass of thanksgiving" on July 23, 1840, at the foot of a mountain on the Idaho side of the Idaho-Montana boundary, where he inscribed the words "Sanctus Ignatius Patronus Montium, ora pro nobis. Die Julii 23, 1840" — Garraghan calls this "the first [Mass] of explicit record in Idaho," though he does not name the exact site. A Montana history blog, Big Sky Words (https://www.bigskywords.com/montana-blog/father-pierre-jean-de-smet-heeds-the-call), traces De Smet's route in detail and places him at Henry's Lake — which sits directly on the Idaho-Montana line — on this date, matching Garraghan's description closely enough that this is very likely the same event. Wikipedia's article on Pierre-Jean De Smet confirms his 1840 journey generally.