Expedition Island

John Wesley Powell, a one-armed Civil War veteran and geology professor, brought his boats to Green River on the new Union Pacific in May 1869 and pushed off downstream into the canyons of the Green and Colorado, which no survey had mapped. Exactly where that first trip launched has never been proven. The second has: Powell's party camped on this island among its cottonwoods in 1871 and left from here on May 22 for a slower and more careful survey.

The two trips mapped the last large unknown country in the continental United States, and the thinking Powell drew from them, about how little water the arid West had and how its land and water ought to be surveyed and settled, fed a new federal approach to conservation, reclamation and survey. The island was made a National Historic Landmark in 1968, nearly a century after the trips. In 1871 it was one island; it is two now, divided by a channel.

It is a city park, with a stone marker to Powell, a river path through the cottonwoods and a put-in for floating the Green through town.