in the Red River Plains area which runs along the Texas border in Southeastern Oklahoma the elevations are

The Red River, or sometimes the Red River of the South, is a major river in the southern United States of America. It was named for the red-bed country of its watershed. It is one of several rivers with that name. Although it was once a tributary of the Mississippi River, the Red River is now a tributary of the Atchafalaya River, a distributary of the Mississippi that flows separately into the Gulf of Mexico. It is connected to the Mississippi River by the Old River Control Structure.