"A DESOLATE, GRIM BEAUTY," said this park's namesake, who hunted bison and dabbled in cattle ranching on its stark rolling prairies and broken badlands in the 1880s. Most visitors sample the park from their cars via scenic drives in one of its two unitsNorth and South, separated by 45 miles as the eagle flies; a hardy minority brave the Easy-Bake summer climate to hike the park's long looping trails. The most tantalizing local adventure, however, lies mostly outside park boundaries: MOUNTAIN BIKING the Maah Daah Hey Trail, 96 unpaved and remote miles that connect the two park units not far from the Montana border. Fat-tire junkies are already calling the trail, completed just three years ago, "the new Moab." Heady stuff, but consider the evidence: the nation's longest uninterrupted bikeable track, with some surprisingly demanding stretches, winding through buttes, canyons scooped out by the Little Missouri River and its feeder streams, rain-sculpted hoodoos, steep ravines, sagebrush valleys, thick stands of cottonwood and juniper, dry riverbeds and wet ones too. Four backcountry campgrounds spread out along the way either have potable-water wells, or will by sometime this summer, so you can make yourself at home where the buffalo really do roam (antelope, wild horses, and rattlesnakes, too). Bikes aren't allowed within national park boundaries, so a spur trail out of Sully Creek State Park does an end-around to the west to skirt the South Unit. Take care not to spook the hikers and equestrians you'll occasionally encounter along the Maah Daah Hey (a Mandan Indian term meaning either "grandfather" or "be here long"). Factoring in the heat, through-cyclers should allow at least five days to complete the trail, though backroads access also allows for a variety of sampler day rides; be forewarned that rain transforms the trail's surface clay into a nasty, slick gumbo. Whichever direction you ride, arrange for a shuttle pickup to get back to your car through Badlands Guide Service (701-225-6109) or Little Knife Outfitters (800-438-6905), which also rents bikes.
WHEN TO GO: Spring rains generally taper off after mid-June. If you can wait, a killing frost usually arrives by September 10 or so, cooling the daytime swelter, zotzing mosquitoes, and triggering the onset of fall colors.
ANNUAL VISITORS: 438,391. (High: July, 117,191. Low: December, 1,210.)
MORE CHOICE ADVENTURE: If the river's high enough, CANOE the Little Missouri through both sections of the park and the grasslands between110 miles of drifting through high banks, casting for catfish, camping in cottonwood groves, and occasionally walking your boat through rocky shallows. Paddlers often put in at Medora and finish up at U.S. 85 near the North Unit. River conditions are usually best mid-May to mid-June; check water levels on the Web at nd.water.usgs.gov (click on the Current Streamflow Conditions link).
HEADLAMP READING: Exploring the Black Hills and Badlands: A Guide for Hikers, Cross-Country Skiers, and Mountain Bikers, by Hiram Rogers; Theodore Roosevelt National Park: The Story Behind the Scenery, by Bruce M. Kaye and Henry A. Schoch
LOCAL SPECIALTY: If all that meat on the hoof gets your mouth watering, the Iron Horse Saloon and Restaurant in Medora grills up a mean buffalo steak.
INSIDE SCOOP: Cyclists should Slime their tires and bring a patch kit and at least two spare tubes. The Maah Daah Hey's prickly-pear cacti and sharp rocks biteand so will your ride if you aren't prepared for flats.
PARK HEADQUARTERS: 701-623-4466, www.nps.gov/thro. (For Maah Daah Hey trail information, see the Dakota Prairie Grasslands Web page at www.fs.fed.us/r1/dakotaprairie/mdhtl.htm, or www.maahdaahhey.com.)