sentences:  According to the U.S. Census Bureau, the county has a total area of , of which is land and (0.02%) is water.It is divided between a high, nearly treeless prairie to the northwest (the southern limit of the High Plains), and a lower semi-desert rangeland to the southeast, by the eastern portion of the steep Canadian Escarpment.The Canadian River, in a deep and narrow canyon, forms the western border with Mora County; the southwest border runs along the edge of the Bell Ranch land in San Miguel County.