Exploring Big Thompson River in Colorado


The Big Thompson River in northern Colorado holds a unique place in the state’s geography, history, and culture. While its headwaters originate in the high peaks of Rocky Mountain National Park, the river flows east through scenic canyons, tranquil lakes, and lively communities before joining the South Platte River near Greeley.

The Big Thompson gained nationwide attention in 1976 when a catastrophic flood ravaged the region, causing extensive damage and loss of life. But thanks to substantial flood control projects and a resilient community, the Big Thompson River valley has rebuilt and flourished in the decades since.

Today, the Big Thompson corridor offers visitors gorgeous mountain vistas, a wealth of outdoor recreation, fascinating historical sites, and a chance to experience authentic small-town charm. Whether you’re looking for adventure, education, or simple relaxation, you’re sure to be enchanted by the many charms of the Big Thompson River valley.


  • The Big Thompson River flows through scenic northern CO from Rocky Mountain National Park east to the South Platte River.
  • A devastating 1976 flood brought the Big Thompson national attention, but the region rebounded.
  • Today, the river corridor offers outdoor recreation, historical sites, and small-town hospitality.

The Area’s Unique Natural Wonders

The headwaters of the Big Thompson River begin high in Rocky Mountain National Park, nourished by snowmelt and glacial runoff from the rugged peaks and valleys of the Continental Divide. As the river descends eastward, it has carved remarkable geologic features like the narrow, sheer-walled Big Thompson Canyon, with rock walls rising over 1,000 feet high in places.

The river broadens into wide mountain meadows and lakes, including sparkling Lake Estes at the eastern entrance to Rocky Mountain National Park. Further east, the Big Thompson fills Lake Loveland, a popular summertime recreation destination for its swimming beaches, fishing access, and kayak-friendly waters.

As the river leaves the foothills and enters the Great Plains, the landscape shifts to rural farm country. Many communities trace their earliest settlements to pioneers building homesteads on the fertile soils near the river during Colorado’s early boom periods.

That agrarian influence remains today in events like the Corn Roast Festival in Loveland and the Harvest Festival in Berthoud. Towns also celebrate their Western heritage with annual rodeos, parades, and fairs. And the riverside hamlet of Drake pays homage to its past as a refuge for prohibition-era moonshiners with an annual Moonshine Festival.

For literary buffs, Estes Park offers the annual Stanley Film Festival, showcasing horror and thriller genres of film in the historic Stanley Hotel that inspired Stephen King’s novel “The Shining.” Music lovers can tune into Berthoud’s annual Berthoud Day celebration and Loveland’s long-running Sculpture in the Park exhibition.

The Lasting Impact of the 1976 Big Thompson Flood

On July 31, 1976, a devastating flash flood along the Big Thompson River forever altered the landscape and psyche of the region. In the deadliest flood in Colorado’s recorded history, over 35,000 cfs of water deluged Big Thompson Canyon, destroying 418 homes and 52 businesses and killing 144 people.

In the flood’s aftermath, government agencies re-evaluated their flood prediction capabilities and developed better streamflow and paleoflood measurement systems to better understand Big Thompson’s flood hydrology. This includes an extensive study of geologic evidence of prior historic mega-floods in the watershed.

The Big Thompson also underwent massive flood control infrastructure projects, including doubling the size of Lake Estes and expanding Olympus Dam to create Lake Estes’ current capacity of over 43,000 acre-feet. Meanwhile, the Bureau of Reclamation renovated and fortified the Colorado-Big Thompson (C-BT) Project’s critical water delivery system from the Colorado River Basin eastward.

Outdoor Recreation for All Interests

Despite its turbulent history, the present-day Big Thompson River corridor entices visitors with its wealth of outdoor recreation. In the upper watershed around Lake Estes and Rocky Mountain National Park, visitors can find spectacular hiking and wildlife viewing along the Big Thompson itself or on trails through adjoining valleys. Anglers can cast for brown, rainbow, and brook trout in the cold mountain waters.

Closer to Loveland, rafting companies offer guided tours through the gentle rapids of the Big Thompson or its tributary, the Little Thompson River. Through Loveland, riverside parks and trails allow easy access for fishing, tubing, or wildlife viewing along the shores.

As the Big Thompson nears Fort Collins, popular recreation abounds at Horsetooth Reservoir, with boating, swimming, scuba diving, and excellent fishing for walleye, smallmouth bass, and trout. To the east of I-25, gateway parks along the Big Thompson provide take-out access for float trips, concluding with the river joining the South Platte.

Conservation Efforts Preserve the River Ecosystem

Thanks to continued conservation efforts, the Big Thompson River ecosystem continues to provide habitat for diverse wildlife while meeting Front Range water needs. A key component is the Colorado River District’s cooperative management of water levels in upper basin reservoirs to balance agricultural usage, municipal supply for cities like Loveland, and in-stream flows for fish and wildlife habitat.

Another major initiative is the Big Thompson Watershed Coalition’s efforts to improve river water quality and riparian habitat through streambank restoration projects along the river’s middle reaches. These projects reduce erosion and sedimentation while expanding critical habitat for fish, waterfowl, and other species.

At the local level, groups like the Loveland Fishing Club promote stewardship of the resource through river cleanup efforts and educational events. And nonprofits like Trout Unlimited provide periodic citizen science stream surveys to monitor the health of the trout fishery below Lake Estes.

Safety and Emergency Preparedness

While the Big Thompson River’s flood control infrastructure minimizes risks today, emergency planners continue working to prepare area communities for potential flooding events. This includes integrated flood warning systems with river gauges and weather monitoring stations, as well as community notification protocols using broadcast media and cellular alerts.

Loveland, Fort Collins, and other municipalities conduct periodic flood response drills to test emergency action plans and coordination with law enforcement, emergency responders, and volunteers. These exercises ensure evacuation routes remain viable and residents understand where to access sandbags, shelters, and other emergency resources.

Past flood relief funding has also helped many flood-prone buildings implement property improvements like elevation relocation and flood-proofing. In the canyon communities hardest hit by the 1976 flood, strict building codes and zoning regulations restrict new construction in the floodplain.

Remembering the Past, Celebrating the Future

Each July, Big Thompson communities come together to honor victims of the 1976 flood while celebrating how far the region has come. Loveland, Fort Collins, and Estes Park all hold memorial events with victim name readings, wreath-laying ceremonies, and float trips.

In Big Thompson Canyon, the small town of Drake holds an inter-faith memorial service at the site of Gage Park, which was one of the flood’s worst damage areas. The park today honors the sacrifice of first responders and serves as a place of solace and reflection.

These remembrances remind residents of the important recovery work done restoring infrastructure, homes, and livelihoods throughout the watershed. Just as importantly, they celebrate the spirit of cooperation and resilience that allowed Big Thompson River communities to transform tragedy into opportunity – and create an even stronger future together.


How can I safely enjoy river recreation along the Big Thompson?

Always check water levels and weather forecasts before setting out, equip your boat with safety gear, wear a life jacket, avoid alcohol intake, and know your limitations. Consider taking guided rafting trips when possible for added insight and support.

Where are the best spots to observe wildlife along the Big Thompson?

Rocky Mountain National Park has excellent trout stream habitat and large mammals like elk, deer, black bears, and bighorn sheep. Mid-river parks and trails around Loveland abound with songbirds, waterfowl, beavers, river otters, and more.

What should visitors know before fishing the Big Thompson?

A valid Colorado fishing license is required for anglers 16 and older. Check regulations for daily possession limits and only keep fish within the legal size ranges to support conservation efforts. Barbless hooks are required in some waters, and live bait is prohibited in Rocky Mountain National Park.

How can I learn more about the 1976 Big Thompson Flood?

The Loveland Museum has an extensive exhibit with flood artifacts and testimonials. Drake and other canyon communities have memorial parks dedicated to flood victims. Guided rafting tours often discuss the flood’s historical impacts during float trips.

Avatar photo

About the author

Simone Weisman

My deep appreciation for nature and active living strongly aligns with the vibrant outdoor culture of Colorado. My enjoyment of yoga, hiking, and exploring scenic trails provides me with a unique perspective that I bring to ReadyColorado.com. This personal passion enriches my ability to connect with and inspire our audience, whether they’re local residents or visitors seeking to explore all that Colorado has to offer.