This 18,000-acre barrier island off the shores of Maryland and Virginia is most famous for the herd of 150 horses that run wild and free. Kids love pitching a tent in the sand next to the ocean, crabbing, and digging for clams. The water is very shallow and safe here; in some spots, toddlers can wade out for yards with you and still be only knee-deep; and there are untold tidal pools, marshes, streams, and shady grottoes to explore on the fringes of nearly 40 miles of beach.
Camping seaside is understandably in demand, so call ahead, up to eight weeks in advance (800-365-2267 or 410-641-3030). The fee for the two bare-bones campgrounds, Oceanside or Bayside, is $14 per night. Assateague doesn't offer any lodges or restaurants on-site -- only a very small, crowded snack bar. For diapers, juice, and supplies, take a five-minute drive over a bridge to neighboring Chincoteague Island, which has all the amenities you'll need.
You'll have to drag your children away from the touch tank stocked with sea stars, urchins, and shellfish at the Barrier Island visitors' center. There, you can also sign up for the popular ranger-led family walks through the saltwater marshes. Be sure to ask the rangers to teach you "hand lining," that is, how to catch crabs with only a chicken neck tied to a piece of string (yuck, but your kids will get a kick out of it). Both the neck and the string are available at Park's Hardware and Supermarket, in Chincoteague. Or rent kayaks from Tidewater Expeditions, also in Chincoteague, to paddle through the bulrushes, where you'll see stingrays and eagles up close ($12 per hour per double kayak; ages 3 and up).
The wild horse herds are beautiful to behold -- but only from a distance. They'll bite little hands that try to feed them apples or other treats.
After you've seen your first few steaming sulphur pots, heaving mud holes, and bubbling mineral springs, you'll wonder if the northwest corner of Wyoming has a bad case of indigestion. That's not far from the truth -- Yellowstone's amazing geological features are the leftovers of a massive volcanic eruption aeons ago. Old Faithful is the most famous attraction here, but there's far more to see -- including 2 million acres of total wilderness to explore.
Yellowstone has six lodge locations, the best of which is the Old Faithful Inn, where your kids can sit on the massive front balcony and eat ice cream while they watch the famous geyser erupt. Your best chance to get a reservation is in September, when the crowds thin out. The park has 12 campgrounds, but only 5 take reservations in advance. (Room and cabin rates range from $58 to $153 per night, campground fees from $15 to $27; 307-344-7311).
Parents of toddlers will enjoy taking a cruise on Lake Yellowstone ($8.75 adults; $4.75 kids ages 2 to 11). School-age kids can see Mother Nature's sense of humor firsthand when they visit the belching and odiferous Dragon's Mouth, the putrid Sour Lake, and the spewing Mud Volcano. For a quieter exploration, join a guided horseback ride from one of three stables through the mountain meadows ($22 per hour; ages 8 and up).
Hold on tight to your child's hand here. The boardwalks through the 220°F hot springs and geyser areas are wide but don't have rails. And the scenic overlooks have low retaining walls.
To kids, bigger is always better. That's why they'll be awed when they stand next to the largest trees on earth at this park in the Sierra Nevada mountain range. Many of the sequoias are as tall as a 26-story building and as wide as a city street. These big trees also spawn long pinecones and gargantuan roots -- providing hours of enjoyment for young ones. Don't spend all of your time at the celebrity trees -- General Sherman and General Grant -- or you'll miss out on kid-friendly trails, which lead to breathtaking mountaintop views and glacial lakes.
Here, you have three lodge areas and 14 campgrounds, but the kids will definitely want to sleep outside under the giant trees. Lodgepole campground ($16 per night; 800-365-2267) has laundry and shower facilities, a post office, and horseback riding. If you're not a camper, check out the new Wuksachi Village and Lodge, which has terrific mountaintop views. (Rates start at $75 per night; 888-252-5757).
Crystal Cave, near Giant Forest, is a marble cavern filled with stalactites and stalagmites. The 60-minute underground tour keeps antsy preschoolers occupied. (You must make advance reservations at the Foothills or Lodgepole visitors' centers; adults, $6; children ages 6 to 12, $3).
This area is home to wild animals such as mountain lions. Stay close together on trails.
Set on 1 million acres of the Rockies in northwestern Montana, Glacier is about as untamed a wilderness as you're likely to find in the lower 48 states. Yes, it can be cold, but isn't that fun in the heat of August? Short cruises ferry visitors to the edges of the mountains, where impromptu snowball fights often break out. Because the park is so isolated, it's easy to find a trail or mountain meadow where your family can commune with nature uninterrupted.
The two lodges at Lake McDonald and Many Glacier offer restaurants, groceries, gasoline, ranger-led hikes, boat cruises, fishing, and horseback riding. (Rates start at $135 per night; 602-207-6000.) If your kids have stamina, the long (7.5 miles) but easy hike to Granite Park Chalet is worth the effort, if only to see the bighorn sheep, mountain goats, and grizzly bears ($60 per person per night; 406-387-5555). Only 2 of 13 campgrounds, Fish Creek and St. Mary, allow reservations ($17 per night; 800-365-2267).
Stop by Apgar Visitor Center, which plans special family activities throughout the summer. Families also love the narrated lake cruises from Many Glacier, St. Mary's, and Two Medicine, offered by Glacier Park Boat Company, in which guides point out moose and grizzly bears dozing in the piney shadows, then drop you off to hike on trails intersecting with lakes and glaciers (prices subject to change: adults, $11; kids ages 4 to 12, $5; 406-257-2426).
Rocks at the edges of the lakes and streams are tempting to play on but slippery. Have your kids wear water shoes to help prevent falls.
It's no wonder that this 800-square- mile forest in North Carolina and Tennessee is the most visited of all the national parks; it bursts with bright mountain rhododendron in spring, offers cool mountain air in summer, and is a haze of gold and red in the fall. But what kids especially love is the focus on the good old days. Consider planning a family trip around the annual Mountain Life Festival, a daylong demonstration of pioneer harvest activities, in September.
The park's only lodge is a five-mile hike from the park entrance, at the top of Mount LeConte; reservations are recommended a year in advance ($76.50 per person per night; $61.50 ages 10 and under; 423-429-5704). The park offers ten campgrounds: The most family-friendly in Tennessee is Cades Cove, which offers bicycle rentals and hay- and horse rides. In North Carolina, Smokemount campground is close to the Mountain Farm Museum, a collection of historic buildings. Reservations for both are required during peak season; call five months in advance ($15 per night; 423-436-1231).
Kids ages 5 to 12 can earn a Junior Ranger badge after learning about the settlers of the Southern Appalachians. The Cades Cove Nature Trail is a half-mile stretch that's uncrowded and ideal for less energetic little feet. During the summer, costumed "pioneers" make soap and dye wool here.
It's so tempting to splash into the park's many rivers and streams that many people don't stop to consider just how fast the current is. Even light afternoon showers can cause a sudden rush in the streams, so keep your children on the banks with you as soon as the raindrops start to fall.
For kids, being here is like playing in the best, most gigantic sandlot ever created. Fifteen thousand acres on the southern curve of Lake Michigan provide miles of beaches, bogs, wetlands, and forests. The dunes are multistory mountains of sand; kids love scrambling to the top, surveying the horizon for ships, and sliding down. Conquering Mount Baldy, a 125-foot dune, is a rite of passage for locals and tourists alike.
The lakeshore has only one campground, Dunewood, which is available on a first-come, first-served basis ($10 per night, April through October). Chesterton, LaPorte, and Michigan City offer affordable hotels, motels, bed-and-breakfasts, and kid-friendly eateries.
The highlight for kids on ranger-led tours is the insect-gobbling sundew and pitcher plants at Pen Hook Bog. Preschoolers love the baby pigs and chicks at Chellberg Farm, and little pioneers learn about 19th-century life at Bailly Homestead's trapper cabin.
Lake Michigan currents are highly unpredictable. Rangers advise swimming strictly at the West Beach, the only life-guarded area.
A whole secret world underneath the ground? Even today's kids, raised on Hollywood special effects, are awed by the longest recorded and mapped cave system in the world -- more than 350 miles. There's plenty to do topside, too, from canoeing on gentle rivers to hiking the bountiful trails.
The park's single lodge, Mammoth Cave Hotel, fills up fast because it's just a stone's throw from the cave entrance, so make reservations as early as you can ($78 per night; 270-758-2225). The Headquarters Campground, one of three in the park, is popular with families because it's also close to the cave and has the most amenities, such as laundry and shower facilities, grills, and a store ($13 per night; 800-967-2283).
At just over an hour long, the Travertine tour ($7 adult; kids 6 to 12, $4) is recommended for preschoolers. Kids ages 8 to 12 who like getting dirty love the two-and-a-half-hour Trog tour ($8), in which they don hard hats and headlights and crawl with rangers into crannies of the cave that their parents never get to see. Cave tours fill up fast, especially during the peak summer months, so reserve spots for your family at least three weeks in advance. Ticket prices depend on the particular tours you choose but range from $3.50 to $35 per person (800-967-2283).
There are no bathrooms in the caves. Make sure little ones go just before you leave on a tour -- or you'll both be very sorry!
In A.D. 550, ancestral Puebloan people made their homes in the canyons, cliffs, and mesas of the southern Colorado Rocky Mountains. Today their architecture is not only intact but stunning -- and makes for an outstanding learning vacation for kids. Not much is hands-off here -- visitors climb up and down ladders, edge along narrow shelves of rock, and wiggle through small tunnels to explore the networks of cavelike dwellings.
If you can, visit in early fall, when the crowds are light. The park offers only two places to settle in for the night. Morefield campground charges $12 per night and has a laundry facility but doesn't take advance reservations. Or you can sleep in the clouds - literally -- at the Far View Lodge, elevation 8,200 feet. Reservations should be made at least two months in advance ($98 per night; 800-449-2288).
The best guided tour for kids ages 3 and up is the Balcony House hike, which is nicknamed the Indiana Jones tour because you'll feel like an action hero as you tiptoe along the cliffs. Tour fees are $1.75 per person.
Watch your kids like a hawk. The mesas can drop nearly 500 feet to the valley floor, and most of their edges are unprotected.