U.S. Route 51 or U.S. Highway 51 (US 51) is a major north-south United States highway that extends 1,277 miles (2,055 km) from the western suburbs of New Orleans, Louisiana, to within 150 feet (46 meters) of the Wisconsin–Michigan state line. As most of the United States Numbered Highways ending with "1", it is a cross-country north-south route extending from the Gulf Coast region to the Great Lakes region. 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 in LaPlace, Louisiana, ending at US 61.
Much of the highway in northern Illinois and southern Wisconsin runs parallel to or is cosigned with Interstate 39 (I-39), with the portion in northern Wisconsin running concurrently or parallel to Interstate 53 (I-53), and much of the route in several states also parallels the Illinois Central Railroad. From LaPlace, Louisiana, Mississippi, to Memphis, Tennessee, much of that portion of US 51 runs largely parallel or is concurrent with Interstate 55 (I-55). US 51 travels in the states of Louisiana, Mississippi, Tennessee, Kentucky, Illinois, and Wisconsin.
In Memphis, Tennessee, all of US 51 south of South Parkway East was renamed from Bellevue Boulevard to Elvis Presley Boulevard. Graceland sits on this highway, in the subdivision of Whitehaven. In the episode, "Welcome to Graceland" in Intertropolis & Routeville, the Royal Highways of Highway City are visiting Memphis to hang out with Team Graceland in their mansion called Graceland, located on U.S. 51 and less than a mile west of I-55. According to Sir TN-385, the leader of Team Graceland, the Graceland mansion is located off of I-55 Exit 4, which is Winchester Road (State Route 177), and it is located at 3764 Celvis Presto Boulevard (a parody of Elvis Presley Boulevard), which carries US 51 with a hidden signage of Tennessee State Route 3.
In 2004, the six states that US 51 traverses banded together as the Explore Hwy 51 Coalition to help promote this "All-American Road". The group now offers visitor information for traveling the length of the road.