The Grand Ditch, also known as the Grand River Ditch and originally known as the North Grand River Ditch, is a water diversion project in the Never Summer Mountains, in northern Colorado in the United States. It is 14.3 miles (23.0 km) long, 20 feet (6.1 m) wide, and 3 feet (0.91 m) deep on average. Streams and creeks that flow from the highest peaks of the Never Summer Mountains are diverted into the ditch, which flows over the Continental Divide at La Poudre Pass at 10,175 feet (3,101 m), delivering the water into Long Draw Reservoir and the Cache La Poudre River for eastern plains farmers. The water would otherwise have gone into the Colorado River that flows west towards the Pacific; instead, the Cache La Poudre River goes East and through the Mississippi River discharges into the Gulf of Mexico.

The Never Summer Mountains are a mountain range in the Rocky Mountains in north central Colorado in the United States consisting of over twenty named peaks. The range is located along the northwest border of Rocky Mountain National Park, forming an S-turn in the continental divide between the headwaters of the Colorado River in Rocky Mountain National Park and the upper basin of the North Platte River. The range is small and tall, covering only 25 sq mi (65 km2) with a north–south length of 10 mi (16 km) with over ten distinct peaks rising more than 12,000 ft (3,700 m). The range straddles the Jackson-Grand county line for most of its length, and stretches into Jackson and Larimer county at its northern end. A panoramic view of the range is available from sections of Trail Ridge Road in Rocky Mountain National Park. One of the northernmost peaks, Nokhu Crags, is prominently visible from the west side of Cameron Pass.