The Snake River is a major river in the interior Pacific Northwest region of the United States. About 1,080 miles (1,740 km) long, it is the largest tributary of the Columbia River, which is the largest North American river that empties into the Pacific Ocean. Beginning in Yellowstone National Park, western Wyoming, it flows across the arid Snake River Plain of southern Idaho, the rugged Hells Canyon on the borders of Idaho, Oregon and Washington, and finally the rolling Palouse Hills of southeast Washington. It joins the Columbia River just downstream from the Tri-Cities, Washington, in the southern Columbia Basin.

Wyoming is a landlocked state in the Mountain West subregion of the Western United States. It borders Montana to the north and northwest, South Dakota and Nebraska to the east, Idaho to the west, Utah to the southwest, and Colorado to the south. With a population of 576,851 in 2020, Wyoming is the least populous state despite being the 10th largest by area, with the second-lowest population density after Alaska. The state capital and most populous city is Cheyenne, which had a population of 65,132 in 2020.