The purpose of this legislation is to protect certain rivers and streams in the Greater Yellowstone Ecosystem in Montana by designating them as part of the Wild and Scenic Rivers System. This designation aims to preserve the natural beauty, recreational opportunities, and ecological health of these waterways for both current and future generations. Key provisions of the legislation include the designation of specific segments of the Madison River, Gallatin River, Hyalite Creek, Cabin Creek, and the Middle Fork of Cabin Creek as either recreational or scenic rivers.