Ashley supervised the building of “bull boats” - clumsy crafts of buffalo hides stretched over a willow frame and led 7 men down the Green River. His was the first recorded river trip on the Green.

The voyagers passed by Expedition Island on Sunday, April 25th, 1825. They walked around many rapids including Ashley Falls, now under Flaming Gorge Reservoir.

They continued downriver through the Green’s canyons until they arrived in the Uinta Basin (now Utah) on June 16th. From there, Ashley left the river and made his way back to this area for the first of the great annual rendezvous held on Henry’s Fork in July 1825.

Though not widespread, word of Ashley’s decent of the river gradually spread in the “States” letting others know that river travel down the Green was possible. Later mountain men used dugout canoes made from cottonwood logs to float the Green.