The Big Thompson River is a scenic and challenging waterway that originates in Rocky Mountain National Park's Forest Canyon, flowing approximately 78 miles eastward through the Front Range of Colorado. This river system drains the eastern slopes of the Continental Divide, passing through Estes Park and the Big Thompson Canyon before joining the South Platte River near Greeley. Paddling opportunities on the Big Thompson are diverse and exciting, with sections ranging from calm flatwater to intense Class V rapids.

The upper reaches near Estes Park offer technical whitewater, including the popular 1.1-mile Big Tommy run, which challenges experienced kayakers with Class III-IV rapids. Downstream, the 11.5-mile stretch from Lake Estes to Drake provides a mix of Class II to IV+ rapids, with some sections potentially reaching Class V+ at higher flows. The river's difficulty varies significantly, demanding strong intermediate to expert skills for most whitewater sections. Paddlers should be prepared for continuous action, tight maneuvers, and potentially dangerous hydraulics, especially in the canyon sections.

Spring runoff typically peaks in late May to early June, offering the most intense whitewater. However, controlled releases from Lake Estes can provide good paddling conditions throughout the summer and into early fall. The section below Lake Estes is particularly popular for after-work runs among local paddlers.

The Big Thompson's ecosystem supports a variety of wildlife, including trout, elk, and bighorn sheep. The river corridor is known for its stunning canyon scenery, with towering granite walls and lush riparian zones. Key landmarks include Lake Estes, the town of Drake, and various parks like Forks Park and Narrows Park. Access points are numerous, with popular put-ins at Lake Estes, Estes Park Dam, and various locations along Highway 34, which parallels much of the river's course.

Historically, the Big Thompson River has played a crucial role in the development of northern Colorado, particularly through the Colorado-Big Thompson Project, which diverts water for agricultural and municipal use. The river also bears the memory of a catastrophic flood in 1976, which reshaped the canyon and led to significant changes in flood management and river access.

Safety is paramount on the Big Thompson. Paddlers should be aware of numerous low-head dams, diversion structures, and the potential for rapid water level changes due to dam releases. Some sections, particularly below Lake Estes, are regulated for artificial flies and lures only, emphasizing the river's importance for both recreation and conservation. While most runs on the Big Thompson are day trips, the variety of sections allows paddlers to create multi-day adventures by combining different stretches, from the challenging upper reaches to the more moderate lower sections near Loveland.