When the town was founded by the Rock Island and Gulf Railway in 1903, it was simply called "Rock Island" until it was changed to Glenrio in 1908, derived from the Scottish term "Glen" for "small valley" and the Spanish "rio". for "river", although it is neither in a valley nor on a river.
The New Mexico-Texas state line runs right through Glenrio, leading to some oddities. The mail (1935-1985) belonged to New Mexico, but was delivered and sorted at the train station on the Texas side. There were no bars on the Texan side because alcohol was not allowed to be served in that part of Texas, while the gas stations were only on the Texan side because of the higher gasoline tax in New Mexico. In addition, the time zone boundary between Central Time (Texas) and Mountain Time (New Mexico) runs here. Although never more than 30 people lived here, it even published its own newspaper until 1934.
Only during the shooting of "The Fruits of Wrath" in 1939 did the place have significantly more "residents". In 1913 the Ozark Trail was built from Amarillo towards Las Vegas, which was later integrated into Route 66. In 1938 the road was completely paved. In the 1950s, it was expanded to four lanes even in Glenrio, with large cement blocks as direction dividers, before the city's demise was heralded in 1955 with the abandonment of the railway. The final death knell came in 1973 when the Interstate was completed. Gradually all businesses were closed. The Post survived the longest. It was only abandoned in 1985 when only 2 residents lived in the town. In 2008, the Glenrio Welcome Center opened on the interstate and was designed for one million visitors per year. That would be 2739 per day.