The steep country that hemmed in the river was never ideal for human habitation. In 1980, Congress made the isolation official, designating the river and its surrounding mountains the largest chunk of the wilderness system in the Lower 48. The Frank Church–River of No Return Wilderness, sometimes just called “the Frank,” stretches across 2.3 million acres in the part of Idaho that starts to get skinny. The river running through it carves a long, forested gorge deeper than the Grand Canyon.
