The boom years: 1926 through the early 1960s
Glenrio existed before Route 66 — it was platted in 1903 as a railroad water-stop along the Chicago, Rock Island and Pacific Railway, with a small population of railroad workers and a handful of ranching families across the surrounding High Plains. The town's name combines "glen" (valley) and "rio" (river) in a slightly fanciful nod to a regional landscape that is actually flat, dry, and treeless. For its first two decades the town was a minor agricultural and rail community of perhaps a dozen families.
Route 66 changed everything. When the original 1926 Route 66 alignment was routed directly through Glenrio along the Texas-New Mexico border, the town pivoted almost overnight from a sleepy railroad stop into a Mother Road service community. The 1930s and 1940s brought a wave of small business development — gas stations on both the Texas and New Mexico sides of the border (each side exploited different state regulations, with Texas-side stations selling gasoline that New Mexico travelers could not get on their side and vice versa), a state-line bar that operated on the New Mexico side because Deaf Smith County, Texas, was dry, several diners and cafes, and a row of tourist courts and motels stretching along the highway.
Glenrio's peak years were the 1940s through the early 1960s. Population hovered around 30 permanent residents but the town served thousands of Route 66 travelers per week during the peak summer travel months. The Little Juarez Diner, the State Line Bar, the Texas Longhorn Motel, the State Line Motel, and the various filling stations were all operating simultaneously, and Glenrio functioned as a small but real Route 66 service economy — the last (or first) stop before crossing into the next state.