Black Mesa State Park, Oklahoma
From the Oklahoma Tourism web site:
Black Mesa is located in Oklahoma’s panhandle along the tri-state border with Colorado and New Mexico. Black Mesa takes its name from the layer of black lava rock that coated the mesa about 30 million years ago. Visitors can hike to the top of the plateau, Oklahoma’s highest point at 4,973 feet above sea level, while in the Black Mesa Nature Preserve.
I saw a prong horn antelope while I was there. I hadn’t realized they came that far east.