This national monument, about 2 hours north of Grand Junction, is really two separate parks divided by the Utah-Colorado border. One side takes a close-up look at the world of dinosaurs, while the other opens onto a wonderland of colorful rock, deep river canyons, and a forest of Douglas firs.

About 150 million years ago, a river and sufficient vegetation made this region a suitable habitat for dinosaurs. Most of their skeletons decayed and disappeared, but in at least one spot they were preserved under a layer of sediment, when the river dried up and they died of thirst.

The Dinosaur Quarry and visitor center that provided access to it was closed in July 2006 and will remain closed indefinitely until much-needed structural repairs can be completed sometime around 2011. In the meantime, there is a temporary visitor center near the Jensen, Utah, entrance that has fossil displays, exhibits, films, and additional information. From Dinosaur, Colorado, head 20 miles west on U.S. 40 to Jensen, Utah, and then go 7 miles north into the park. This is the only place in the monument to see dinosaur bones.

However, even though exploration of the quarry area has been curtailed, there is still plenty to do here, especially on the Colorado side. Encompassing 325 square miles of stark canyons at the confluence of the Yampa and Green rivers in Colorado, the national monument also has hiking trails to explore, spectacular panoramic vistas, and the thrill of white-water rafting. Your first stop should be the Canyon Area Visitor Center, located about 2 miles east of the town of Dinosaur, Colorado, at the intersection of U.S. 40 and Harpers Corner Drive.

Allow about 4 hours for the scenic Harpers Corner Drive. This paved 62-mile round-trip drive has several overlooks offering panoramic views of the gorges carved by the Yampa and Green rivers, the derby-shaped Plug Hat Butte, and a variety of other colorful rock formations. The drive also offers access to the easy .25-mile loop that is the Plug Hat Nature Trail and the moderately difficult 2-mile round-trip Harpers Corner Trail, highly recommended for a magnificent view of the deep river canyons. In addition to several developed trails, experienced hikers with the appropriate maps can explore miles of unspoiled canyons and rock benches.

A superlative way to see this rugged country is on the river, crashing through thrilling white water and gliding over the smooth, silent stretches. One of the best authorized companies running the Yampa and Green rivers through the monument is Hatch River Expeditions (tel. 800/342-8243 or 435/789-4316; www.hatchriver.com). Prices start at $78 for adults, $68 for kids ages 6 through 14 for a 1-day trip; multiday trips over longer stretches are also available. The season generally runs from mid-May through mid-September, depending on water levels. A complete list of authorized river-running companies is available from monument headquarters.

The rivers here are not safe for swimming or wading; the water is cold, and the current is stronger than it may first appear.

Fishing in the Green and Yampa most often yields catfish, northern pike, and smallmouth bass, although there are also some trout. Several endangered species of fish -- including the razorback sucker and humpback chub -- must be returned unharmed to the water if caught. You'll need Utah and/or Colorado fishing licenses, depending on which side of the state line you're fishing.

There are campgrounds in both sections of the monument, but no showers or RV hookups, and camping fees range from $8 to $12 per night.

The national monument entrance near Dinosaur, Colorado, is about 110 miles north of Grand Junction. From Grand Junction, head west on I-70 about 12 miles to exit 15, turn right (north) onto Colo. 139, and go about 75 miles to Colo. 64; turn left and follow it west for 20 miles to the town of Dinosaur. Then turn right onto U.S. 40 and go east about 2 miles to the monument entrance. The monument is open around the clock, and the outdoor visitor center in Utah is open daily year-round, except Thanksgiving, Christmas, and New Year's Day. Hours in summer are 8:30am to 5:30pm, with shorter hours the rest of the year. The Canyon Area Visitor Center in Colorado is open daily May through late October 8:30am to 4:30pm but closed weekends in winter. The admission fee, charged only during summers on the Utah side, is $10 per vehicle and $5 per person for those on foot, motorcycles, or bicycles.

For information, contact Dinosaur National Monument, 4545 E. U.S. 40, Dinosaur, CO 81610-9724 (tel. 970/374-3000 or 435/781-7700; www.nps.gov/dino). In addition, the nonprofit Intermountain Natural History Association, 1291 E. U.S. 40, Vernal, UT 84078-2830 (tel. 800/845-3466; www.inhaweb.com), offers numerous publications on the park's geology, wildlife, history, and dinosaur fossils.

Note: This information was accurate when it was published, but can change without notice. Please be sure to confirm all rates and details directly with the companies in question before planning your trip.