The starkly different terrain, of course, offers very different recreational opportunities, such as alpine skiing, tons of hiking and cross-country skiing, fishing, and the chance to immerse oneself in utter solitude in the Bob Marshall Wilderness Complex—380,000 acres of untamed land.

Natural history and American history are closely entwined in this forest, and the very informative interpretive center sheds light on Lewis and Clark's exploratory route up the Missouri, as well as the history of Native Americans and Thomas Jefferson's vision of an expanding America.

Hike the Wall of China
With almost 1,700 miles of trails, Lewis and Clark National Forest is a hiker's haven. Two wilderness areas—the Bob Marshall and the Scapegoat—lie within forest boundaries, meaning motorized vehicles are far at bay. This section of the "Bob" is especially beautiful because of the Chinese Wall, a 22-mile-long, 1,000-foot-tall escarpment that's part of the Continental Divide. If you're looking to take advantage of a hike without the noise of ATVs or anyone except other hikers, try the Our Lake Trail, a moderately difficult four-miler. For something tough, try the Willow Creek Plateau, a difficult 6.5-mile trek through a forest of lodgepole pine. The forest also boasts seven national recreation trails; one of these is the Two Medicine-Mowitch Basin trail off Route 2, a long but gentle trek of 28.3 miles.

Tour Mountains and Prairie
Looking for a bit of history with your beauty? The Kings Hill National Scenic Byway—US Highway 89—that runs through the plains part of the forest and up into Great Falls, gives you a bit of both. You'll pass through the village of Ringling (yes, named after that Ringling) and then Castle Town, a former mining camp named for the spires of the Castle Mountains, which loom overhead. In White Sulphur Springs, don't miss soaking in the mineral baths. And just north of town, you'll find access to the Smith River. The road takes you up into the Douglas firs and pines of the Little Belt Mountains. Drive north through the open rolling hills and the road becomes heavily forested. Here's another must-see: Memorial Falls, the trail for which is located just past Many Pines campground. Peak times for this drive are in summer, when the wildflowers are out in force, and fall, when the leaves explode in brilliant colors.

More on scenic driving in Lewis and Clark National Forest

Ski Teton Pass
While not nearly as extensive as that big gorilla of Montana downhill, Big Mountain, the ski resorts in and near Lewis and Clark serve up good skiing. In Choteau, the Teton Pass resort has 26 trails spread over 150 acres. Showdown, in the Little Belt Mountains, has 34 trails and gets 20 feet of snow per year. Cross-country more your thing? The Silver Crest trail system comes complete with four easy-to-intermediate loop trails, groomed weekly, that go on for 12 kilometers through the snowy backwoods. They begin and end at the winter sports parking lot off US Highway 89.

Catch Your Limit
In Montana, the name of the fishing game is trout. And in the Lewis and Clark forest, you'll find 1,600 miles of streams and many small natural and man-made lakes full of cutthroat, brook, and rainbow—along with some mountain whitefish. In the forest's Rocky Mountain Division, check out the Sun River and Dearborn River. Out on the plains, the biggest draw is the fishing on Smith River. As you float along the river dragging and casting, you'll have the added benefit of beautiful scenery, since you're floating through a deep canyon. Large numbers of rainbow make for easy fishing. And as the tributaries increase the depth of the riffles and pools, the fish become bigger, and brown trout make up more of the population. A word of preparation: Floating on this river is immensely popular—apply in February for a permit.

See Montana-Size Wildlife
The combination of Rocky Mountains, open meadows, gushing rivers, and rolling foothills makes Lewis and Clark a haven for just about any kind of creature found in Montana. Take a float down the Smith River for the chance to see black bears, elk, and mule and whitetail deer, which often gather on the banks. Hiking or driving through the Rocky Mountain section of the forest? Perfect: That's where you'll find mountain goats and the state's largest herd of bighorn sheep. Keep an eye on the sky as well, since bald eagles and peregrine falcons rule the air. And waterfowl? You'll find migrants just about everywhere you go.

More on wildlife in Lewis and Clark National Forest