The southwestern portion was originally part of the Ozark Trails, paralleling the
El Paso and Southwestern Railroad, and was originally given the numbering of
State Highway 33. SH 33 continued into Texas farther south in the Panhandle, following the former
Ozark Trail. The northern Panhandle portion was originally assigned to
State Highway 56, paralleling the
Chicago, Rock Island, and Gulf Railroad. When the
U.S. Highway System was unveiled in 1926, the northern section was assigned to U.S. Highway 54, while the southwestern portion was assigned to
U.S. Highway 366. The US 366 designation was canceled in 1932 when other sections of the highway were added to an adjusted US Route 70. This section was added to US 54 in 1934, and has retained its numbering since. By 1939, the corresponding state highway designations had been canceled. The highway continues on its original routing except for realignment in 1990 in El Paso, with the old route becoming US Business Route 54 and Texas Loop 478. Most of the current US 54 in El Paso is a limited-access highway known as the Patriot Freeway which, as of 2016, was only partially completed. ==Future==