I think geographically hurts some of the attendance, but shouldn't be much effect if UND had good numbers in the past. A hour down the road you have a national champion, and Grand Forks is North East ND, so if your not coming from the west, your on the edge of the FBS Minnesota fan base to the east, and people to the north already have ice, so they are too worried with hockey.
Its a little easier to see SDSU getting more people with being the only major college team in the region(Besides USD(Who has some attendance problems as well from what I seen in the past)) My hometown an hour west of Brookings had dozens of people going to State Games at Coughlin Alumni games quite often, and I hear of people from Watertown and Sioux Falls(large populatation hub with no D1 school) that travel to Brookings weekly as well.