Expedition Island, Nature reserve in Green River, Wyoming, United States

Expedition Island is a nature reserve spanning several acres along the Green River with recreational grounds, playground facilities, and multiple access points. The island connects to both riverbanks via bridges, making it accessible for visitors interested in water-based recreation.

John Wesley Powell launched his exploration expeditions of the Green River and Colorado River from this location in 1869 and 1871. These journeys were critical to mapping regions that remained largely unknown to the outside world at that time.

The city of Green River marks the Powell expedition history with annual events, and the channel east of the two islands is used for whitewater rafting and kayaking. A stone marker in the park commemorates John Wesley Powell's activities.

The park provides picnic areas, fishing spots, and water sports access with convenient bridge connections from both sides of the river. The open layout and facilities make it straightforward to plan a day of outdoor recreation and water activities.

The island was originally larger; river erosion split it into two, and only the southern part became the park. The northern island is undeveloped and overgrown, and is not believed to hold the historic launch site. A stone marker on the park grounds commemorates John Wesley Powell's expeditions.