Dinosaur National Monument

Dinosaur National Monument, straddling the Utah-Colorado border in the eastern Uinta Mountains, is one of the most geologically and paleontologically significant places in the American West — a monument protecting both the world’s most accessible and richly productive dinosaur fossil quarry (the Quarry Exhibit Hall, where 1,500+ bones of 11 dinosaur species are visible in the tilted sandstone wall) and the spectacular river canyons of the Green and Yampa Rivers, the only un-dammed major tributaries of the Colorado River.

The monument’s dual character — the world-class fossil quarry and the extraordinary river-canyon wilderness — makes it one of the most compelling and undervisited national monuments in the country. Dinosaur National Monument is a treasured paleontological and geological icon shared between Utah and Colorado.

Dinosaur National Monument offers visiting the Quarry Exhibit Hall (the primary paleontological experience — a modern building enclosing the tilted Morrison Formation sandstone wall where more than 1,500 dinosaur bones of 11 species are embedded and visible in the rock in three dimensions, as they were deposited 149 million years ago; rangers give interpretive talks; this is one of the great paleontological experiences in North America, accessible to visitors of all ages), river rafting the Green River and Yampa River canyons (the primary backcountry experience — the monument contains some of the finest whitewater rafting in the American West, including the famous Yampa River — one of the last un-dammed rivers in the Colorado watershed; multi-day trips require permits and outfitter coordination), hiking the trail system (Harper’s Corner Trail offers the finest canyon overlook, looking down 2,500 feet into the Green River canyon), rock art viewing (Fremont Culture petroglyphs at the Cub Creek area), stargazing (the monument is a designated Dark Sky Park), and 4WD road exploration. The dinosaur quarry, the river canyons and the rock art are the singular draws.

Spring (April through June) is the finest river-rafting season (the Yampa River runs only in spring when snowmelt fills it; by late June it is too low to raft). Spring is also the finest season for the Harper’s Corner hike and the canyon overlooks — the cottonwoods in the canyon bottom are leafing out and the light is excellent. Summer is hot (90-100°F) but the Quarry Exhibit Hall is climate-controlled and excellent any time; river rafting on the Green River (which is dam-regulated and runs all summer) is excellent in June and early July. Fall is beautiful for hiking. Spring for the Yampa rafting and the canyon hiking, and any season for the quarry, are the highlights.

Dinosaur National Monument’s fossil quarry was discovered by paleontologist Earl Douglass of the Carnegie Museum in 1909 — he found 8 articulated tail vertebrae of an Apatosaurus in the Morrison Formation sandstone and recognized immediately that the tilted sandstone layer was extraordinarily rich in dinosaur fossils (the ancient river sandbar trapped dinosaur carcasses for millions of years, creating one of the densest fossil concentrations known). President Woodrow Wilson proclaimed the quarry site a national monument in 1915. In the 1950s, the Bureau of Reclamation proposed the Echo Park Dam in the monument’s canyon, which would have flooded the Green and Yampa River canyons; the successful campaign to defeat the Echo Park Dam (led by David Brower and the Sierra Club) was a landmark moment in American conservation history, establishing the principle that national monuments are off-limits to development.

Dinosaur National Monument exposes one of the most complete geological records of the American West — the famous Quarry sandstone is a Morrison Formation river sandbar deposit (Jurassic, 149 million years old) that was tilted to a 60-degree angle by the Uinta Mountain uplift, exposing the fossils in cross-section. The monument’s river canyons (the Green River and Yampa River have cut 2,500+ feet deep into the Uinta Mountain uplift) expose rocks ranging from Precambrian basement to Cretaceous age in a spectacular sequence of red sandstone, gray limestone and colorful shale formations. The Green and Yampa Rivers were established before the Uinta Mountain uplift began — as the mountains rose, the rivers maintained their courses, cutting ever deeper into the rising rock. The antecedent river canyons, the Morrison Formation quarry and the Uinta Mountain geology created Dinosaur’s extraordinary character.

Dinosaur National Monument’s diverse habitats — the river corridor, the canyon walls, the sagebrush uplands, and the Uinta Mountain forests — support exceptional wildlife. Bighorn sheep are commonly seen on the canyon walls along the river. River otters (reintroduced to the Yampa) are occasionally seen from river trips. Peregrine falcons nest in the canyon walls. Black bears and mountain lions inhabit the Uinta Mountain areas. Golden and bald eagles soar over the canyons in winter. Mule deer and pronghorn are common on the upland plateaus. The Green River corridor is an important flyway for migratory songbirds in spring. The monument’s wildlife diversity reflects the range of habitats compressed into a small area.

Dinosaur National Monument protects the last un-dammed segment of the Yampa River — one of the most ecologically significant remaining free-flowing river ecosystems in the Colorado River watershed. The un-dammed Yampa supports native fish populations (including the endangered Colorado pikeminnow, bonytail, humpback chub and razorback sucker) that cannot survive in the regulated flows below dams. The Green River (regulated by Flaming Gorge Dam) has a reduced but still significant native-fish population. Protecting the Yampa’s free flow and the monument’s river-corridor riparian habitat is the most critical ecological conservation priority.

Dinosaur National Monument holds a treasured place among the paleontological and conservation icons of the American West — the world’s most accessible and richly productive dinosaur fossil quarry (1,500+ bones visible in the rock), the site of the landmark conservation victory against Echo Park Dam in the 1950s, the location of the last un-dammed major tributary of the Colorado River, and one of the most geologically spectacular and undervisited national monuments in the country. Its dinosaur quarry, its river canyons, and its conservation heritage make it exceptional. Dinosaur NM is a treasured icon of Utah and Colorado.

Dinosaur National Monument has two primary visitor areas: the Utah side (the Quarry Exhibit Hall and the Cub Creek rock-art area — accessible via UT-149 north from Jensen, UT, which is 13 miles east of Vernal on US-40) and the Colorado side (Harper’s Corner and the river overlooks — accessible via US-40 through Dinosaur, CO). The two sides are about 30 miles apart by paved road. Vernal, Utah (13 miles west of the Jensen entrance) has full services. An NPS entrance fee applies (America the Beautiful Pass accepted). River rafting requires permits (contact the monument for permit information and outfitter recommendations). Check NPS for current conditions, fees and river-permit information before visiting.

The National Park Service manages Dinosaur NM. The most critical conservation feature is the un-dammed Yampa River — the free-flowing Yampa supports the last population of endangered native fish in the upper Colorado watershed; any attempt to dam the Yampa in or near the monument should be vigorously opposed. Visitors help by not disturbing any fossil or rock-art site (it is illegal to collect fossils or damage rock art — the penalty is severe), practicing strict Leave No Trace on river trips (pack out all human waste; use fire pans; pick up all trash), respecting bighorn sheep and other wildlife (maintain distance), and supporting the monument’s native-fish restoration program.

The river canyons involve real wilderness conditions: the Yampa and Green rivers have class III-IV rapids (on a 6-point scale; rafting experience or an outfitter is required), extreme summer heat (100°F in the canyon), remote location (no cell service; evacuation requires ranger helicopter or days of hiking), and flash-flood risk in the side canyons. The quarry area and visitor facilities are safe and accessible. Do not attempt the river canyons without proper experience, equipment and permits. Register with the park if entering the backcountry. Rattlesnakes (prairie rattlesnake) are present throughout the monument; watch where you step and put your hands. Respect the river wilderness conditions, the heat, the rattlesnakes and the remote location.

NPS entrance fee (America the Beautiful Pass accepted). River trips require advance permits (apply through NPS lottery; commercial outfitters hold their own permits). Fossil and rock-art sites: no collecting, touching or damaging any fossil or rock art. Camping: designated sites only (river campsites during permit trips; campground at Split Mountain and Green River). Pets on leash; not allowed on some trails. Pack out all trash (river trips: pack out human waste in a groover). No fires except with approved fire pans on river trips. Check NPS for current rules, river conditions and permit process before visiting.

The city of Vernal, Utah (13 miles west of the Jensen entrance — the “Dinosaur Capital of the World,” with the Utah Field House of Natural History and the Vernal Dinosaur Museum), the Uinta Mountains (the only major east-west mountain range in the contiguous US; High Uintas Wilderness is accessible from the south), Flaming Gorge National Recreation Area (30 miles north — the Green River reservoir with excellent fishing and canyon scenery), and the Colorado towns of Steamboat Springs and Grand Junction (via US-40 and I-70) define the regional context. Dinosaur NM is the finest stop on any US-40 cross-country route and deserves a minimum of a full day.

Arrive at the Quarry Exhibit Hall when it opens (9 AM) and take the first ranger talk of the day for the full fossil-quarry interpretation — understanding which species each bone came from and how the deposit was formed transforms the experience from “interesting wall of rocks” to “extraordinary 149-million-year-old river scene.” Then drive the Harper’s Corner Road on the Colorado side (a 32-mile paved road through spectacular canyon country, ending at the 2-mile Harper’s Corner Trail overlooking the confluence of the Green and Yampa Rivers 2,500 feet below) — the finest canyon overlook experience in the monument. For the Yampa River, plan 6-9 months in advance for the permit lottery (the Yampa trips are among the most sought-after permit lottery entries in the national park system).