All around the Plains, there are many physical landforms. Most of this region is flat and grassy, but the land gets increasingly rockier and mountainous as it goes west. In the north is the Red River, which creates the boundary between Texas and Oklahoma. Along the south is another river, the Colorado River, which stretches from the Gulf of Mexico to northern New Mexico. In the east lays the Coastal Plains, and in the west the Caprock Escarpment forms a natural boundary between the North Central Plains and the Great Plains.
Vegetation consists mostly of grasses, such as thick grass and short thick grass. In the Cross Timbers sub-region, hardwood trees are plentiful, but other trees, such as small oak and mesquite, also grow.
Vegetation consists mostly of grasses, such as thick grass and short thick grass. In the Cross Timbers sub-region, hardwood trees are plentiful, but other trees, such as small oak and mesquite, also grow.