The staccato calls blare out of the mist, startlingly loud. We scan what little we can see of the wide valley for the source of the noise. It sounds prehistoric, a remnant of a wilder epoch, which perfectly describes what we’ve seen so far: To explore the far northeast corner of Yellowstone National Park is to travel back in time.

In early fall, the roads through this part of the park are as busy as you’d expect. Herds of tourists gather to observe herds of bison, elk, and antelope from the road that winds through the Lamar Valley, while fly fishers line the waterways. But my hiking partner and I wanted to escape the crowds for a true Yellowstone backcountry experience, where we could find the spirit of America’s first national park. Upon checking in at the Tower Ranger Station we learned that we’d have our pick of campsites along Slough and Pebble Creeks—if we could rise to the challenge of the seldom traveled trail over Bliss Pass.

From Pebble Creek Campground trailhead we started up the Pebble Creek drainage to a view over the Lamar Valley, its scythe of grassland peeking out between forested ridgelines. With the road now out of sight and earshot, the park was suddenly brooding, quiet, and empty—capital “W” wilderness.