From the record
“The Antelope Hills are a series of low hills in the bend of the Canadian River in northwest Roger Mills County, Oklahoma, near the border between western Oklahoma and the Texas panhandle. They were a major landmark for the Plains Indians and travelers on what is now the western plains of Oklahoma.”
Wikipedia article Antelope Hills, Oklahoma, CC BY-SA 4.0.
One of 4 National Register listings published here for Roger Mills County · listed in 1978 · category: Site.
Sources: the Wikipedia article · the case file at the National Archives · the National Register database, National Park Service · the Wikipedia article