Northwest Oklahoma ranges from dry and flat to an area with mountain ranges and mesas, a testament to the Southwest Tablelands ecoregion that dominates the area. Canyons and grasslands, such as the Rita Blanca National Grassland, help to give Northwest Oklahoma a distinctive Southwest-like landscape, differing from other parts of the state. Black Mesa, the state's highest peak at 4,973 feet, is part of a large range of mesas in the panhandle which stretch into New Mexico. Another mesa range, the Glass (or Gloss) Mountains, sits in the center of Northwest Oklahoma, just south of the Cimarron River along Highway 412. Great Salt Plains Lake, one of the largest inland salt lakes in the United States, is located near Alva.