La Prairie de la Messe (Green River Rendezvous site, Horse Creek), Wyoming

July 5, 1840

Location	La Prairie de la Messe (Green River Rendezvous site, Horse Creek)
State/Territory	Wyoming
County	Sublette County
Modern Diocese	Diocese of Cheyenne
Historical Diocese	Diocese of Quebec(?)
Date	July 5, 1840
Priest	Fr. Pierre-Jean De Smet
Religious Order	Society of Jesus (Jesuits)
Rite	Roman (Latin) Rite
Expedition	De Smet's 1840 Journey West — see the full route, Fr. De Smet's Journey West (1840) →
Confidence	confirmed

Photos

Documentation

WyoHistory.org (Wyoming State Historical Society)

Notes

On July 5, 1840, De Smet held the first Catholic mass in the area that is now Wyoming. Independently corroborated by the Wyoming State Historic Preservation Office's National Register listing (wyoshpo.wyo.gov): the first Catholic Mass to be held in the area that now comprises the State of Wyoming. Attended by roughly 2,000 people at the annual rendezvous. Also verified at Diocese of Cheyenne history page https://files.ecatholic.com/25338/documents/2020/6/wyocatholicchurchinwy.pdf?t=1593459820000

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