Although US 60 initially stretched less than halfway across the country, due to its late creation, it was soon extended west to Los Angeles. One auto trail — the Atlantic and Pacific Highway - and three other U.S. Highways played a part in this extension. The Atlantic and Pacific Highway had been organized in 1921, and connected New York City with Los Angeles. The original alignment of U.S. Route 70 entered Clovis, New Mexico from the east, as it does now, but continued west to Holbrook, Arizona. Crossing US 70 at Clovis was the El Paso-Amarillo U.S. Route 366. Finally, U.S. Route 164 was created by 1928, stretching northeast and east from Amarillo to U.S. Route 64 and U.S. Route 81 in Enid, Oklahoma. The American Association of State Highway Officials approved the first part of the extension in May 1930, following the rest of Missouri's Route 16 to the Oklahoma state line, and several state highways to Enid, before absorbing US 164 to a terminus at Amarillo. The remainder to Los Angeles was approved at AASHO's June 1931 meeting, and involved a number of other changes. US 60 replaced US 366 from Amarillo to Clovis, where it continued west along US 70 to Springerville, Arizona. The remainder of US 70 to Holbrook, Arizona became a new U.S. Route 260, while US 60 followed the Atlantic and Pacific Highway, which it had picked up at Vaughn, New Mexico, southwest and west through Phoenix to Los Angeles. US 70 was not truncated to Clovis, but was instead redirected southwest along US 366 to El Paso, and later reached Los Angeles itself, though most of the route west of Globe, Arizona overlapped US 60.