The original U.S. Route 66 passed through eight states: Illinois, Missouri, Kansas, Oklahoma, Texas, New Mexico, Arizona, and California.
Traveling west from Chicago, the route crossed Illinois and Missouri before briefly entering Kansas. It then continued through Oklahoma, the Texas Panhandle, New Mexico, Arizona, and California, ending at the Pacific coast.
Kansas had the shortest section, at roughly 13 miles, while New Mexico had one of the route’s longer stretches. The highway’s path crossed farmland, prairie, desert, mountain country, and major cities, giving it an unusually varied identity.
People sometimes mistakenly count Los Angeles as a separate state or omit Kansas because the road was so short there. Route 66 remained an eight-state highway throughout its recognized alignment, although its precise path changed repeatedly through relocations and bypasses.