Want to explore Colorado’s famed Fourteeners without the crowds? Head to the San Juan National Forest—specifically the Weminuche and Lizard Head wilderness areas. Protecting the headwaters of the Rio Grande and San Juan Rivers, Weminuche alone is three-quarters the size of Rhode Island. You’ll find lakes and hiking trails galore up here, plus those 14,000-foot (4,300-meter) peaks, like Mount Eolus.

Rather than head to 5,550 acres (2,200 hectares) Arkansas’ Hot Springs National Park, the second-smallest national park in the country, visit nearby 1.2-million-acre (500,000-hectare) Ozark-St. Francis National Forest. Here you’ll find waterfalls, bluffs, mountains, spring-filled caverns, dense hardwood forests, rivers, and lakes. Popular activities include hiking Pam’s Grotto, climbing Sam’s Throne, or kayaking the Buffalo National River, one of the longest undammed rivers in the Lower 48.

Olympic National Park isn’t the most crowded national park, but it does have a few spots that get Yellowstone levels of foot traffic. For an alternative, try the Olympic National Forest, which almost completely surrounds the national park. Check out the 4-mile (6-kilometer) Quinault Rain Forest Loop Trail for a wildflower-filled mountain trek, or hike one of the 6,000-foot (1,800-meter) peaks of the Mt. Skokomish Wilderness. With mostly lower elevations, many spots here can be hiked year-round.

Considering that the main appeal of The Great Smoky Mountains National Park is well, trees, the surrounding Cherokee National Forest offers plenty of those, plus ample other opportunities for adventure. Here’s a short list of things you can do in the Cherokee National Forest: hike the Appalachian Trail; white-water raft the Ocoee River; hike the Iron Mountains; kayak Watauga Lake; bike the 30-mile (48-kilometer) Tanasi Trail; and count waterfalls in the Rock Creek Gorge Scenic Area.

While Bryce Canyon is fantastic for red rocks, insiders know that Dixie is too. Covering 2 million acres (800,000 hectares), Utah’s Dixie National Forest offers plenty to do and tons of room to spread out. It's home to spots such as Yant Flat and the Candy Cliffs, which are reminiscent of Arizona’s The Wave—without the required lottery access. For a family-friendly adventure, hit Hell’s Backbone Road, a scenic “backroad,” for a high-elevation, panoramic adventure.

Sitting between Yosemite National Park and Kings Canyon National Park, Sierra National Forest often gets overlooked, but it shouldn’t. Famed photographer Ansel Adams and naturalist John Muir both loved this area. Here, you’ll get a little bit of Yellowstone, Sequoia, and Kings Canyon all rolled into one. Scope out giant redwoods in McKinley and Nelder groves, hot springs at the Mono Hot Springs campground, granite masses at Fresno Dome, and Sierra Nevada views at White Bark Vista.

Yellowstone sees about 1 million visitors a month come summer—and the best way to avoid them is to adventure through Wyoming’s Bridger-Teton National Forest, one of the Lower 48’s largest at 3.4 million acres (1.4 million hectares). Here, you'll find hundreds of hiking and biking trails, lakes and rivers for fishing and picnicking, camping sites, and even glaciers. If you’re looking for more skillful hiking, check out the Wind River Range in the Pinedale Ranger District.