“That stone’s like a greased bowling ball,” my fishing guide, Jack Flemming, told me. I was standing waist-high in the Gallatin River, plodding against the rapid current. There was not a lick of action as far as rainbow trout were concerned, but that was beside the point.

Rangy lodgepole pines, which constitute 80 percent of the 2.2 million-acre Greater Yellowstone Ecosystem, smelled mountain fresh, and sunbeams shimmered on the water. My mind was both blank and hyper-focused: cast the fly rod, mend, repeat. Truth is, I couldn’t have cared less about catching a fish. I was content to lean into the wilds of Montana, perhaps the most consequential wilderness in the continental United States.