Montana Headwaters Legacy Act This bill designates specified segments of the following rivers and creeks in Montana as wild, scenic, or recreational rivers Smith River, Tenderfoot Creek, Gallatin River, Hyalite Creek, Taylor Creek, Madison River, Bear Creek, Boulder River, Hellroaring Creek, Lake Fork Rock Creek, Rock Creek, Slough Creek, Stillwater River, West Boulder River, West Fork Stillwater River, West Fork of Rock Creek, Yellowstone River, Cabin Creek, Middle Fork of Cabin Creek, and Clarks Fork of the Yellowstone River. No land or interest in land located within the boundary of such a river segment may be acquired by the Department of the Interior or the Department of Agriculture without the consent of the owner of the land or interest.