The St. Ignatius Mission is a landmark Catholic mission located in St. Ignatius, Montana. It was founded in 1854 by Jesuit priests Pierre-Jean De Smet and Adrian Hoecken. The current mission church was built between 1891 and 1893, and listed on the National Register of Historic Places in 1973. The mission church serves the St. Ignatius parish within the Missoula Deanery of the Roman Catholic Diocese of Helena.