U.S. Route 412

The longest straight road in the United States isn't the famous Route 46 in North Dakota (the longest straight section of which runs for just over 27 miles).

There are two separate sections of the same highway in the Oklahoma Panhandle that surpass Route 46's length by a substantial margin. From Boise City to just west of Guymon, Highway 412 runs razor's-edge straight for 47.7 miles. And as if that wasn't enough, when Highway 412 resumes its straight and narrow ways 24 miles to the east, it proceeds to run perfectly straight through the farmlands of western Oklahoma from Hardesty to just east of Slapout for another 65.5 miles. 

On a sad note, there are many abandoned homes and farmhouses along the route, nevertheless, a wonderful, peaceful road to travel.