Traveling north from Missoula through the Flathead Reservation we found the beautiful St Ignatius Mission church.  The original cabins for chapel and convent are still on the premises.  St Ignatius is famous for the 58 original paintings by Brother Joseph Carignano which cover the interior. Fr Hoecken, one of two priests who founded the mission along with Fr DeSmet, describes the place better than I:

". . . I arrived at the place designated on the 24th of September and found it such as it had been represented–a beautiful region, evidently fertile, uniting a useful as well as pleasing variety of woodland and prarie, lake and river–the whole crowned in the distance by the white summit of the mountains, and sufficiently rich withal in fish and game. I shall never forget the emotion of hope and fear that filled my heart, when for the first time I celebrated Mass in this lovely spot, in the open air."

Their story is here.  Pictures of the interior here.