10. Guadalupe Mountains

Guadalupe Mountains National Park is worth a visit just for a look at the towering face of El Capitan, part of what park officials bill as the world’s best example of a fossilized reef. The park drew 198,000 visitors in 2009. Late October and early November is the best time to visit, to take in the changing foliage in McKittrick Canyon. Located within an hour’s drive south of the more popular Carlsbad Caverns National Park in New Mexico, if you’re heading to that park you could easily fit a visit to Guadalupe Mountains National Park on the same trip.
9. Dry Tortugas

Located some 70 miles west of Key West, Florida, Dry Tortugas National Park is one of the most isolated U.S. national parks. That explains why only 52,000 people visited the park in 2009. Accessible only by boat or seaplane, the park offers great diving and snorkeling opportunities, and history buffs will enjoy touring Fort Jefferson, a 19th century U.S. military installation that is the largest masonry structure in the Western Hemisphere.
8. Great Sand Dunes

Great Sand Dunes National Park and Preserve in southern Colorado draws fewer than 300,000 visitors a year. The most amazing feature in the park are its 750-foot sand dunes, the tallest in North America, but there are also plenty of other sights to take in, from 13,000-foot mountain peaks to alpine lakes and old-growth forests.
7. North Cascades

The Pacific Northwest contains several popular national parks, but North Cascades National Park in Washington doesn’t share that distinction, drawing only 27,000 visitors in 2009. Here is what everyone else is missing, in a statement on the park’s website: “Jagged peaks, deep valleys, cascading waterfalls and over 300 glaciers.” The park also boasts nearly 400 miles of trails.
6. Isle Royale

Located in the middle of Lake Superior, the only access to Isle Royale National Park is by boat or floatplane, which might explain why less than 15,000 people took the trouble to do that in 2009. The park features 45-mile-long Isle Royale, although hundreds of other small islands nearby are under park jurisdiction. There are roughly 165 miles of hiking trails, including the 40-mile Greenstone Ridge Trail. In addition to camping, there is a lodge available for overnight stays.
5. Great Basin

Great Basin National Park, which became a national park in 1934, celebrated its 75th anniversary in 2009 by welcoming its 3 millionth all-time visitor. To put that in perspective, in 75 years, the Nevada park has drawn fewer visitors than the 3.3 million people who visited Yellowstone National Park in 2009. That’s not to suggest Great Basin is in any way comparable to Yellowstone, yet it’s worth a visit. By day, check out 13,063-foot Wheeler Peak. Or, bring your camping equipment for a night under the stars, as Great Basin’s remote location in the desert makes it an ideal place for astronomy buffs. A 2005 National Park Service study found Great Basin to be one of the darkest areas in the U.S.
4. Congaree

Congaree National Park, in central South Carolina, is a relatively recent addition to the National Park system, added in 2003. The park is known for its old-growth floodplain forest, which is believed to be the largest remnant of such forest in North America. A canoe or kayak may be the best way to enjoy the park, but there are also more than 20 miles of hiking trails.
3. Black Canyon of the Gunnison National Park

Any national park that includes the word “canyon” in its name should be worth checking out, right? Yet Black Canyon of the Gunnison National Park in southwest Colorado drew a rather paltry 171,000 visitors in 2009. By contrast, the better-known Rocky Mountain National Park about 150 miles to the northeast drew an estimated 2.8 million visitors in 2009. If you’re going, take a drive along the south rim, the more popular side, and hike along one of the trails.
2. Capitol Reef

Located in southern Utah, Capitol Reef National Park draws a little more than a half million visitors each year, a respectable figure, yet that’s a fraction of the visitors who flock to neighboring national parks in Utah, such as Zion (2.7 million visitors in 2009), Arches (1 million) and Bryce Canyon (1.2 million). Perhaps travelers are a bit dazed after running through the spectacular beauty of Utah’s best national parks and decide to skip the Capitol Reef and nearby Canyonlands National Park, which drew only 436,000 visitors in 2009. The Capitol Reef itself is part of a 100-mile-long protusion in the earth’s crust. Take a hike, bike some of the roads in the park, or bait a hook for fishing in the Fremont River.
1. Big Bend

Located in Texas, right on the Mexican border, Big Bend National Park is a long way from population centers, which keeps visitor traffic relatively low, around 350,000 visitors per year. If you make the journey, take a hike on one of the challenging trails in the Chisos Mountains or raft on the Rio Grande River in your own equipment, or with one of the local outfitters. If you’re going, bear in mind this warning posted on the park’s web site: “Visitors should be aware that drug smuggling routes pass through the park.”
