From the record
“Glenrio, formerly Rock Island, is an unincorporated community in both Deaf Smith County, Texas, and Quay County, New Mexico, United States. Route 66, the ghost town sits on the Texas-New Mexico state line.”
Wikipedia article Glenrio, New Mexico and Texas, CC BY-SA 4.0.
One of 2 National Register listings published here for Deaf Smith County · listed in 2007 · category: District.
Sources: the Wikipedia article · the National Register database, National Park Service · the Wikipedia article