OWYHEE CANYONLANDS, Ore.—Drive 50 miles from Boise, Idaho, past the suburbs, exurbs and farms into Oregon, and you’ll find yourself in the largest conservation opportunity left in the continental U.S.

South of the Treasure Valley, fly across the Snake River and the snow-streaked Owyhee Mountains rise to more than 8,000 feet. Here, a vast region known as the Owyhee Canyonlands comes into view. The ...

The last great underappreciated epic river in the Lower 48, the Owyhee weaves through Idaho’s southwestern sage steppes, cutting deep canyons into cliffs of volcanic rhyolite. Surrounded by an ocean ...

Just southwest of Boise lies one of the last vast swaths of solitude in the United States. The Owyhee Canyonlands, with stunning red gulches, winding rivers and a moon-like landscape where a volcano ...

The Owyhee River takes you on an intoxicating desert run. In 1865, after fording the Owyhee and crossing the valley, Major G. Kimball wrote in his diary, “I was brought up to believe there is a Hell ...