San Juan River, Utah. Kayaking past the Mexican Hat formation east of the town of Mexican Hat on the San Juan River. This river takes its name from the San Juan Mountains of southwestern Colorado where the melting snows of the Colorado Rockies form its headwaters. In 300 river miles between its headwaters at Wolf Creek Pass west of Durango, Colorado and its terminus in Lake Powell, the river drops 1.5 vertical miles  through a variety of spectacular Rocky Mountain and redrock canyon landscapes. For the last 85 miles above the stagnant waters of Lake Powell at Clay Hills Crossing, the San Juan meanders through deep limestone canyons reminiscent of the Grand Canyon.