ND 91 is really short, reports KFYR-TV in Bismarck. (Video un-embeddable.) The route in Harvey, along US 52 between Jamestown and Minot, is signed at 0.28 miles. That is just a hair longer than IA 405 was signed 1980-2003. I found this story because of this last sentence, which has issues:
According to a 2014 report from the Iowa Department of Transportation, U.S. Highway 77 travels over the Missouri River into South Dakota at .31 miles long. That means Harvey’s Highway 91 could be the shortest highway in the United States.
First, US 77 travels over the Missouri River into Iowa at that distance, NOT South Dakota. Second, US 77 is overall an extremely LONG highway, ending all the way down in Brownsville, Texas. The state-specific mileage is irrelevant when considering the total distance of a highway.
Correction-worthy nitpicking aside, it’s neat that there’s a story about North Dakota’s shortest highway, and that the town would like to publicize it.