High Quality Content by WIKIPEDIA articles! The U.S State of Colorado includes the headwaters of several important rivers. The state is divided generally East to West by the Continental Divide. East of the Continental Divide, surface waters flow via the North Platte River, the South Platte River, the Republican River, the Arkansas River, the Cimarron River, the Canadian River, or the Rio Grande to the Gulf of Mexico. West of the Continental Divide, surface waters flow via the Green River, the upper Colorado River (formerly the Grand River), or the San Juan River into the Colorado River and on to the Gulf of California. Colorado also has three significant endorheic basins: the San Luis Closed Basin in the San Luis Valley, and the Bear Creek Basin and the White Woman Basin spanning the Colorado-Kansas border south and north of the Arkansas River.