History of the Colorado River

Indigenous History

For more than a thousand years before modern exploration, the canyons of the Colorado River supported thriving Indigenous cultures. Between AD 300 and 1300, the Ancestral Puebloan and Fremont peoples lived, farmed, and built communities across what is now Moab, Canyonlands National Park, and the greater Colorado Plateau. They grew maize, beans, and squash on floodplain terraces, constructed granaries and dwellings in sandstone alcoves, and developed small-scale irrigation systems tied to the river’s seasonal flows.

Remnants are prominent along the river corridor in Canyonlands National Park at sites such as Indian Creek. Guests who raft Cataract Canyon with Mild to Wild travel directly through this cultural landscape. Farther downstream, Glen Canyon once held thousands of archaeological sites before being submerged by Lake Powell.

John Wesley Powell’s Explorations

The Colorado River entered American awareness in 1869, when John Wesley Powell – a one-armed Civil War veteran and geologist – led the first documented expedition through the deep canyons of the Green and Colorado Rivers. Powell’s first descent began on May 24, 1869, in Green River, Wyoming, and followed the Green through Flaming Gorge, Lodore Canyon, Whirlpool Canyon, Desolation, Labyrinth, and Stillwater before meeting the Colorado at today’s Confluence in Canyonlands National Park. From there, Powell’s crew pushed into Cataract Canyon, navigating some of the largest rapids in the system, before continuing through Glen Canyon, Marble Canyon, and the Grand Canyon.

On August 30, 1869, after nearly 930 miles of uncharted river, the expedition ended at the confluence with the Virgin River, a location now submerged beneath present day Lake Mead. The descent was groundbreaking but nearly catastrophic. Powell’s 24-foot modified Whitehall boats were extremely heavy, rigid, and overloaded with supplies – unsuitable for violent rapids – resulting in wrecked boats, lost food, and destroyed equipment. Three men abandoned the expedition just before the Grand Canyon’s most dangerous stretch, never to be seen again. Powell survived, but much of his scientific work remained incomplete.

Powell returned for a second expedition in 1871-1872, again beginning at Green River Station and traveling to the Virgin River terminus. This time his team used purpose-built Whitehall-style boats that were lighter, more maneuverable, and far better sealed against swamping. Improved design, watertight compartments, better logistics, and a trained scientific crew allowed Powell to map, photograph, and document the canyons with precision, shaping America’s understanding of Western geology and water.

Outlaws and the Wild West

As Powell’s era of exploration gave way to the late 19th century, the river’s canyons became havens for outlaws escaping the fading frontier. On June 24, 1889, Butch Cassidy and his partners robbed the San Miguel Valley Bank in Telluride, fleeing west with nearly $20,000 – about $680,000 today. Their escape route carried them through Utah’s Canyonlands, where they crossed the Colorado River near Moab.

From the crossing, Cassidy’s gang disappeared into Robbers Roost, a maze of tributary canyons used to hide horses, cattle, and stolen goods. Once resupplied, they traveled north to Brown’s Park, located in the Green River Valley just below Flaming Gorge Reservoir, one of the Wild Bunch’s most long standing hideouts.

Major Rafting Sections of the Colorado River

Upper Colorado River – Kremmling, CO

Class I–II • Ideal for families, first-timers, and sightseers

The Upper Colorado River flows for 14–25 (depending on the takeout) miles through Hartman and Red Gorge Canyons. Intermittent broad mountain valleys, sandstone cliffs, and cottonwood groves make this section a scenic delight. Its mix of gentle Class I & II rapids and calm pools makes it one of the best introductory rafting sections in Colorado. Two and three day trips offer beach camping, stargazing, and side hikes.

Shoshone – Glenwood Canyon, CO

Class III–IV (depending on water levels) • Great for adventure seekers & experienced rafters

The Shoshone stretch squeezes intense whitewater into 2 miles of rapids, followed by up to 7 miles of scenic floating downstream. Rapids like Maneater, The Wall, and Tombstone thunder through a metamorphic gorge with 2,000 foot walls.

Ruby Horsethief Canyon – Grand Junction, CO

Class I • Perfect for families, sightseers, and overnight campers

The 25-mile Ruby Horsethief section is a calm desert float through towering Entrada and Wingate sandstone cliffs. Sandy beaches, shaded camps, wildlife viewing, and peaceful water make it a top choice for families and groups seeking a mellow overnight wilderness experience.

Westwater Canyon – Eastern Utah

Class III–IV • Best for adventure seekers and experienced rafters

The 17-mile Westwater Canyon corridor drops through black schist narrows and red-rock walls, delivering punchy Class III & IV rapids like Funnel Falls, Sock-It-To-Me, and Staircase. Its 1.7-billion-year-old rock and big wave whitewater earn it the nickname “The Little Grand Canyon.”

Moab Daily (Castle Valley/Fisher Towers) — Moab, UT

Class I–III • Great for families, first-timers, sightseers

This 13-mile stretch of the lower Colorado River flows through the settlement of Castle Valley below the iconic Fisher Towers rock formations. Splashy Class II waves, glowing red-rock walls, and panoramic views create one of the most scenic and accessible family rafting trips in the western United States.

Cataract Canyon – Canyonlands National Park, UT

Class III–V • Ideal for multi-day adventure travelers & big water fans

Nearly 96 miles long, Cataract Canyon delivers enormous Class III-V whitewater. The section begins just below the confluence of the Green and Colorado Rivers. Multi-day trips (2–5 days) combine calm canyon floats, ancient sites, slot canyons, red-rock walls, and some of the biggest waves in North America.

Grand Canyon – Arizona

Class III–V • For serious adventure seekers & expedition travelers

Stretching 226 miles, the Grand Canyon delivers some of the greatest rapids on earth to the likes of Granite, Horn, Crystal, and Lava Falls. A pillar of rafting in the American West, it is no wonder it is one of the 10 wonders of the world. Multi-day trips last 7–18 days, depending on the method of river travel (rowing or motor) and allocated time for wondrous side hikes.

River Conditions & Seasonality

The Colorado River’s character shifts dramatically with the seasons, driven by snowmelt from the Rockies, desert heat, and upstream reservoir releases. In spring (April through June), melting snowpack pushes the river toward its highest flows of the year. Temperatures across the basin remain cool, with air temperatures ranging from 45-75°F on the Upper Colorado River (including the Upper Colorado and Shoshone sections) and 60–90°F along the Lower Colorado River (Ruby Horsethief, Westwater, Castle Valley, and Cataract Canyon). Water temperatures remain cold, generally 45–52°F on the upper stretches near Kremmling and Glenwood Canyon, and 48-55°F through the lower sections between the Grand Junction and Canyonlands regions. Spring flows often reach their peak: the Upper Colorado commonly runs between 2,000-4,500 CFS, the Castle Valley and Moab Daily stretch between 6,000-20,000 CFS, and Cataract Canyon can surge from 30,000 to over 60,000 CFS in high runoff years. These flows create fast water and powerful hydraulics, especially in the lower canyon stretches, where Cataract Canyon regularly produces Class IV-V whitewater. Guests rafting in spring should expect brisk water, faster river travel, and consistently exciting rapids, with wetsuits strongly recommended.

Late June through July brings warmer and more consistent rafting conditions. Air temperature highs range from 65-90°F on the Upper Colorado and 80-105°F along the Lower Colorado River. Water temperatures warm to 52-60°F on the upper sections and 60–75°F on the lower sections. As the snowmelt diminishes, flows stabilize around 800-1,800 CFS on the Upper Colorado and 3,000-8,000 CFS through Castle Valley and Westwater, and 10,000-25,000 CFS in Cataract Canyon. Rapids in the lower canyon stretches remain strong but become less surging and more predictable, shifting from crashing haystack like waves to more distinct features. This period offers the most comfortable combination of warm weather, steady flows, and approachable rapids, making it the prime season for first timers, families, and scenic floaters across the upper and lower river sections.

Fall (September through October) brings mild days, cool nights, and clear skies along the entire basin. Air temperatures generally range from 50-80°F on the Upper sections and 65-90°F on the Lower sections. Water temperatures remain surprisingly warm after heating all summer. Typical ranges on the upper and lower sections are 52-58°F and 65-75°F respectivley. Flow levels settle into their lowest and most stable point of the season: 600-1,200 CFS on the upper river, 2,000-6,000 CFS through Castle Valley and Westwater, and 5,000-15,000 CFS in Cataract Canyon. These late season flows reveal more beaches, calmer currents, and turn Cataract Canyon into a scenic Class III-IV technical big-drop run rather than the powerful Class V surge seen in early summer. Fall is ideal for guests who value scenery, warm water, and comfortable hiking conditions..

Historical and real time data can be checked for each specific section of the Colorado River on the USGS website. The Upper Colorado Monitoring locations are generally found under the state of Colorado and the Lower Colorado monitoring locations can be found under the state of Utah.