 The county is drained by the North Canadian River and the Canadian River, which both flow through the county from northwest to southeast.According to a study published by the Oklahoma Geological Survey, the North Canadian River drains about 40 percent of the county, the Canadian River drains about 32 percent and the Cimarron River drains about 27 percent (mostly in the northeastern part of the county.About 1 percent of the county is drained by Sugar Creek, which empties into the Washita River, itself a tributary of the Red River.