State Highway 171 serves as a short east–west route between U.S. 75, St. Vincent, the Red River, and Pembina, ND.

Adjoining North Dakota Highway 59 in Pembina was numbered to match then-Highway 59 in Minnesota.

[4] In the 1950s, this route was renumbered 171 when a realigned U.S. 59 was constructed from Lancaster north to Canada.

Minnesota and North Dakota have not yet petitioned AASHTO officials to change the definition of U.S. 75 to follow the routing of 171 and ND 59.

As of 2019, nearby U.S. 75 in Minnesota is still signed to what is now a dead-end at the old Noyes border crossing.