Conveniently close to Denver and running along I-70 in the mountains before heading down Clear Creek Canyon, Clear Creek offers excellent whitewater potential and several big river guide companies operate along its waters. Clear Creek has 25 miles of rafting with rapids rated from grade II to grade IV. There are even some potential grade V sections for the experienced rafter.
The Colorado River, which begins in Rocky Mountain National Park, carved the Grand Canyon and much of the wild landscapes in Utah. While those areas offer more whitewater possibilities there are some good rafting stretches in Colorado particularly Glenwood Canyon just east of Glenwood Springs. This narrow, beautiful canyon has majestic high cliffs of crumbling limestone that were carved by the river. The river has 18 miles of grades II to III whitewater.
Other navigable portions of the river include Gore Canyon, which has mostly grades II to III, with some more serious sections and Horsethief Canyon with up to 20 miles of grades I to II paddling.
The Arkansas River is Colorado's most popular whitewater destination and has up to 100 miles of thrill-inducing rafting possibilities. The Narrows offers 11 miles of grade IV whitewater with great views of the Collegiate peaks. Big Horn Sheep Canyon offers milder whitewater, grades II to III, with views of the Sangre de Cristo Mountains along its 19-mile stretch. Browns Canyon and its 22-mile stretch of grades III to IV whitewater is probably the most popular destination for paddlers in Colorado. Those seeking even more steep thrills can try the grade V sections of the Narrows and Royal Gorge, the latter of which goes under the world's highest suspension bridge.
The Gunnison River cuts through steep, high walls of the Black Canyon, which has the highest vertical cliff in Colorado (the Painted Wall, 2,250 feet high). The Canyon is also very narrow, so rafting there is not to be missed. The Gunnison offers grades I to III rafting.
The Eagle River near Vail offers some popular rapids, as does the Dolores. The North Platte, which flows from Colorado into Wyoming, offers 35 miles of wilderness rafting at grades II toIV.