Question: Which highway that has a junction at Cairo Junction is 1286 miles long?
Related documents: [0]  [DOC] Cairo Junction is an unincorporated community in Alexander County, Illinois, United States. Cairo Junction is located at the junction of U.S. Route 51, Illinois Route 3, and Illinois Route 37 north of Cairo. [END] 
[1]  [DOC] U.S. Route 51 is a south-north United States highway that runs for 1286 mi from the western suburbs of New Orleans, Louisiana to within 100 ft of the Wisconsin–Michigan border. Much of the highway in Illinois and southern Wisconsin runs parallel to or overlaps Interstate 39 (I-39), and much of the route in several states also parallels the Illinois Central Railroad. The highway's northern terminus is between Hurley, Wisconsin, and Ironwood, Michigan, where it ends with a T interchange at US 2. Its southern terminus is Laplace, Louisiana, ending at US 61. [END] 
Answer: 
U.S. Route 51
U.S. Route 51