Onion Valley Road, California1 of 9
This hors categorie (beyond category) climb is one of the toughest you'll find anywhere. You'll gain 5,169 feet in just 12.5 miles and finish at a staggering 9,163 feet in elevation. Not impressed? The Eastern Sierra road is both longer and steeper than the Tourmalet and Galibier, two iconic climbs of the Tour de France.
Photo Credit: Paul Fretheim, Wikimedia
Wheeler Peak, Nevada2 of 9
Located in the Great Basin National Park, you aren't likely to see too many others on this lonely road. It's rated a category-1 climb and is 15.5 miles in length. The road ends at Summit Trailhead, topping out at 10,163 feet.
Photo Credit: Famartin, Wikimedia
Palomar Mountain, California3 of 9
This climb up south cole-grade road is a classic of Southern California. Twenty-one switchbacks and 12.5 miles of climbing at an average grade of 6.9 percent make this route just as steep and severe as your classic climbs in the Tour.
Photo Credit: Visitor 7, Wikimedia
Beartooth Pass North, Montana4 of 9
Starting at 5,675 feet, this epic route climbs along southern Montana before finishing in Wyoming. The gradient isn't that steep, averaging only 3.3 percent, but the views above the tree line are stunning. Total length is 30.4 miles, and the finishing elevation tops 10,947 feet.
Photo Credit: Phil Armitage, Wikimedia
Mount Mitchell, North Carolina5 of 9
This road begins at a shallow gradient, but it does get steeper as you climb up the 24.1 mile stretch of road that leads to the top of Mount Mitchell. Elevation gain is 5,161 feet and you'll have to pass through several tunnels to make it to the top, but the views are worth any inconvenience.
Photo Credit: Ken Thomas
Whiteface Mountain, New York6 of 9
The Alp d'Huez of the east coast, Whiteface is shorter than some of the others, but it's equally challenging. You'll climb 3,566 feet in just 7.9 miles, and the views at the top at the Whiteface Castle visitor's center let you peak into Vermont and Canada on clear days.
Photo Credit: Traumallama
Mount Washington, New Hampshire7 of 9
This road is not for amateurs. Claiming to be one of the toughest climbs in the world, Mount Washington gains 4,727 feet in just 7.8 miles. The average gradient is a staggering 12 percent, with max grades topping 22 percent. As if that isn't challenging enough, 20 percent of the climb is gravel.
Photo Credit: Stilfehler, Wikimedia
Mount Evans, Colorado8 of 9
Featuring the highest paved road in the United States, Mount Evans reaches 14,127 feet above sea level. For anyone who's been that high knows that climbing at 8,000 feet is a lot different than climbing above 12,000. The route from Littleton to Summit Lake is a 100-mile out and back trip with over 10,000 feet of climbing. The way back down should be significantly easier.
Photo Credit: Robertbody, Wikimedia