Originally drawn to the region by rumors of gold on the San Juan in the 1890s, Loper developed a love for the Colorado’s deep canyons.  In 1907 he accompanied two men on a river prospecting and photography trip from Green River, Utah through the Grand Canyon.  Although Loper only went as far as Lee’s Ferry, the trip began a love affair with the river that lasted more than forty years.  In his long career he assisted numerous river expeditions through the canyons, including the Hoover dam survey and a government survey of the San Juan.  

In July, 1949, and nearing 80 years of age, Loper set out with friends to celebrate his birthday in the Grand Canyon.  In Marble Canyon, below Lee’s Ferry, he slumped over, the victim of an apparent heart attack.  His boat capsized and his body was lost until 1975, when it was discovered by a hiker 47 miles downstream.  He died as he lived—on the river—after logging over 7,000 miles on the Colorado River system.

Few river runners have spent so much of their lives on the river and been so clearly identified with it in so many ways as Loper, for whom a memorial stands in the Green River city park. A replica of Loper’s boat is also on exhibit at the museum.