Possessing the highest average elevation of any State, Colorado is bisected by the Continental Divide and is the origin of many important rivers. The west side of the Divide, known as the West Slope, is entirely drained by the Colorado River and its many tributaries; the East Slope, on the other hand, is composed of four major watersheds: the North Platte, the South Platte, the Arkansas and the Rio Grande.
The Colorado River rises along the Continental Divide in Rocky Mountain National Park. Snaking toward the WSW, this famous stream takes in flow from many other rivers, including the Fraser River at Granby, the Blue at Kremmling, the Eagle at Dotsero, the Roaring Fork at Glenwood Springs and the Gunnison at Grand Junction. The White, Yampa and Green Rivers, which drain the high plateau and mesa country of northwest Colorado, join the Colorado River in eastern Utah while the San Juan River, which heads on the south side of the San Juan Mountains, in southwest Colorado, joins the Colorado River in southeast Utah.
The South Platte rises along the Continental Divide at the north rim of South Park. After flowing southeastward, toward Pike's Peak, it angles to the northeast, passes through Denver and enters Nebraska near the northeast corner of Colorado. The North Platte drains North Park, in north-central Colorado, loops through southeastern Wyoming and joins the South Platte in Nebraska; the combined Platte River flows eastward across Nebraska before merging with the Missouri River. The Arkansas rises among the highest peaks in Colorado, near Leadville, flows to the south and southeast, passes through Pueblo and then courses eastward across the High Plains to enter Kansas near the southeast corner of Colorado. Finally, the Rio Grande, famous for delineating the U.S.-Mexican border along the southern edge of Texas, heads in the San Juans of southwest Colorado, flows eastward to the San Luis Valley and then turns southward to enter New Mexico.
