NATURE'S BEST: An autumnal view of one of the many twisting loops on the Buffalo National River.
Randy Olson/National Geographic Stock

Arkansas’ BUFFALO NATIONAL RIVER is one of the country’s last undammed rivers and a great American treasure.

I was maybe a mile into my first hike along the bluffs that surround and define the Buffalo National River when I turned to look back up the trail I’d just come down, noticing how it zigzagged up rock steps, through slippery mud, between two twisted oak trees and out of sight. Perhaps I’d been a little too dismissive of the terrain. Granted, I’m a recent transplant to Arkansas from Nevada, where mountains commonly reach 10,000 feet. But the Ozarks? Please. The highest “peak” in Arkansas, Mount Magazine, is only 2,753 feet. How hard could a hike in these ­“mountains” really be?

But, as they say around here, it’s not that the mountains are high. It’s that the valleys are low.

NOW YOU KNOW: More than 300 species of plants, fish and other sea life reside in the Buffalo National River.

There were easier ways into Hemmed-In-Hollow (an apt name, I was learning), but I wanted to earn my visit to this shady, U-shaped canyon surrounded on all sides by towering limestone bluffs and capped by a 260-foot waterfall, the highest between the Appalachians and the Rockies. And the walk down was glorious: rock formations reminiscent of Utah, an occasional view across the canyon that wouldn’t be out of place in Arizona — even stands of beech, which are rare in Arkansas. Once off the bluff and past a series of small waterfalls, you approach the big falls as you would an altar, eyes up to the heavens. If the wind is blowing, as it was that day, the water waves back and forth like a lawn sprinkler, painting the canyon with sparkling mist.

But as I sat on a boulder facing the falls, eating a sandwich and trying to wrap my head around the idea that I was not somewhere out west, the thought of getting back up to my car was nagging at me. I was going to have to hump it back up the trail before dark. Was there enough daylight left?

What I've come to love about the Buffalo National River since my first visit is that it offers as much or as little adventure as you want. In various trips, I’ve taken an easy stroll along a graded trail to Lost Valley, a string of waterfalls, caves and pools so idyllic it was once named Eden Falls. I’ve also canoed parts of the sometimes-rowdy but generally calm Buffalo National River, following its curves as it cuts from one bank to the next, twisting and turning past towering limestone bluffs and dense forests that are particularly striking when dressed in fall colors. I haven’t made it down the whole river yet; it’s 135 miles long, none of it dammed. Paddling its length could easily fill a week if you aren’t in a hurry. And what a week it would be: camping on gravel bars in the middle of the river; eating fish caught right from the clear, green water; and seeing almost no evidence that you’re anywhere near civilization.