Depending which expert you consult, this is Viola canadensis, var. rugulosa, or V. rydbergii. Either way, this is pretty much the west of the story. Called creeping-root violet by those who would make a distinction, it occurs in AK, AZ, CO, IA, ID, MN, MT, ND, NE, NM, OR, SD, UT, WA, WI, WY, AB, BC, MB, NT, ON, SK, and YT. This image is from Ouray Co CO on 6/22/13.