From the record
“Fort Supply was a United States Army post established on November 18, 1868, in Indian Territory to protect the Southern Plains. It was located just east of present-day Fort Supply, Oklahoma, in what was then the Cherokee Outlet.”
Wikipedia article Fort Supply (Oklahoma), CC BY-SA 4.0.
One of 5 National Register listings published here for Woodward County · listed in 1971 · category: District · built in 1868.
Sources: the Wikipedia article · the case file at the National Archives · the National Register database, National Park Service