Scotts Bluff National Monument & the North Platte River Valley

| NEBRASKA |

As you travel southbound on either U.S. Highway 71 or U.S. Highway 26 from the east or west and enter Scotts Bluff County, your windshield’s suddenly filled with a breathtaking sight of the North Platte River Valley and the Wildcat Hills, which is dominated by the Scotts Bluff National Monument, rising 4659 feet (1420 meters) above sea level and towering 800 feet (244 meters) above the North Platte River. 

| SCOTTS BLUFF NATIONAL MONUMENT

The Scotts Bluff National Monument, named for the fur trapper Hiram Scott, who died here in 1828, is overflowing with human, geological, and paleontological history. Scotts Bluff, known throughout its history as Capital Hills, Convent Rock, Gibraltar, Scott’s Rock, and Scotts Bluff Mountain, has served as a landmark for hundreds of years of human occupation in the Great Plains. It is a sacred location for the Native Americans who inhabited WyoBraska, both past and present. It served as a vital waymarker for early fur trappers, Pony Express riders, and emigrants following the Oregon, California, and Mormon trails on their way to new lives in the West. Today, it is a connection to days gone by for travelers and history buffs who come to learn about its creation and history, hike its trails, and view its geological wonders.

Of the five rocks that make up Scotts Bluff National Monument; Sentinel Rock, Crown Rock, Eagle Rock, Saddle Rock, and Dome Rock- the half dome of Eagle Rock is the most recognized and photographed. Eagle Rock forms the north side of Mitchell Pass, through which countless thousands of emigrants drove their covered wagons single file, and Pony Express riders galloped to deliver mail.

In 1853, Mariett Foster Cummings stated:

“There is a pass-through that is guarded on one side by Sugar Loaf Rock (Eagle Rock), on the other by one that resembles a square house with an observatory (Sentinel Rock). There is one (nearest the river) that is certainly the most magnificent thing I ever saw.”

When standing at the base of Eagle Rock, you can see something unquestionably unique about the geology that forms these colossal escarpments of rock and earth.

There are three different kinds of rock, identified by geologists, which make up the topography of the buttes soaring above the valley floor. Sedimentary (sea bed, river, and dune deposits), igneous (volcanic), and metamorphic (rocks that have been changed by pressure and heat), but the only exposed rock at Scotts Bluff is sedimentary.

The most exposed geological history in the entire state of Nebraska can be seen by hiking the Saddle Rock Trail, which runs along the north face of the Monument, from the Visitors Center to the summit of Scotts Bluff, and has its own tunnel to walk through.

| SADDLE ROCK

About 20 million years ago, Western Nebraska’s landscape was again changing. Evidence at Eagle Rock, Saddle Rock, and along the face of the bluffs suggest that dunes once advanced across the Nebraska Panhandle. The Gering Formation of the Arikaree Group (at the top of the bluffs) records the development of these dunes. Cross-sections of the Gering Formation dunes can be seen on Saddle Rock Trail. The “pipy” concretions of hard calcium deposits stick out of the rock layers. The dunes and “pipy” concretions are scattered together among the layers of sediment, clearly indicating cyclic changes in climate and weather.

During dry periods, the dunes soared to towering heights, while the ceaseless winds of the Great Plains drove them in a relentless march across the Nebraska Panhandle. When it rained, water seeped through the calcium carbonate and cemented the sand into concretions.

Renewed uplift of the plains and further decreasing amounts of water-born and wind-blown sediments allowed rivers and wind to erode the sediment layers about five million years ago. As the uplift of the plains continued, the rocks began to crack and peel away from each other, further weakening them. In some areas, the “pipy” concretion was not cracked, forming a protective cap of harder rock over the top of soft rock and resulting in what we know today as a bluff. Before the last uplift of the plains and the Rocky Mountains and the erosion that followed, the Great Plains of Western Nebraska were at least, if not more, as high as the present top of the bluffs at Scotts Bluff National Monument.

The Saddle Rock Trail is popular with locals as well as visitors. The 1.6-mile (2.4 km) long trail begins at the visitor center parking lot and ascends 435 feet (133 m) to the top of the escarpment. The first 700 yards (630 meters) to Scott’s Spring are wheelchair accessible, crossing prairie grasslands and a juniper-filled ravine at the base of Saddle Rock. Beyond this point, wheelchair use is not recommended because the trail rises steeply for more than 1700 yards (1554 meters) with sharp drop-offs.

| ORIGINS

The origins of Scotts Bluff butte began 80 to 55 million years ago during the Laramide orogeny as the Rocky Mountains were formed west of Scotts Bluff. Over millions of years, weathering and wind erosion deposited windblown and water sediments to the east. These sediments accumulated in layers, burying what would become the North Platte Valley to a height of over 800 feet. The layers became compressed by overlying sedimentary rocks, hardening the material.

At this time, the entirety of what would become the North Platte Valley was flat, with a few small rolling hills dotting the landscape.

Over millions of years, the force of the flow of water from newly formed rivers and wind and weathering erosion began to cut the valley out of the overlaying rock exposing layers of sedimentary rock, which geologists have been able to date to 34 to 20 million years.

Geologists use a system to identify the rock layers that works much like reading the chapters of a book. Each layer reveals different characteristics based on color, grain size, composition, and material thickness, allowing for accurate material dating.

If you dig 250 feet below the North Platte River, you will encounter a thick layer of shale, evidence of a shallow sea that covered the Great Plains until 70 million years ago. As the Sea receded, the Rocky Mountains and the Great Plains began to uplift.

The shale formed at the bottom of the sea and is now the foundation of the promontories surrounding Scotts Bluff. Geologists named this formation the Pierre Shale.

Newly formed rivers and eastward-blowing high winds began carrying weathered sand and silt from the mountains, depositing it across western Nebraska.

The sediments deposited by newly formed rivers became the Orella Member of the Brule Formation in the White River Group, which can be viewed in the badlands north of Scotts Bluff National Monument.

About 33 million years ago, massive, violent volcanic eruptions ravaged south-central and western Colorado depositing volcanic ash in west Nebraska.

This ash is still visible in the Whitney member of the Brule Formation and is mixed with silt. Two distinct ash layers are found in the Whitney Group. The lower layer most likely records one massive super-eruption about 31 million years ago, possibly from the Yellowstone Super Volcano. These layers are visible on Eagle Rock about halfway up the rock face.

Established in 1919 by a Presidential Proclamation, the Scotts Bluff National Monument now preserves and protects over 3,000 acres of mixed-grass prairie, rugged badlands, towering bluffs, historic trail remnants, and riparian areas along the North Platte River.

Each year, more than 100,000 visitors walk in the footsteps of pioneers on remnants of the Oregon Trail or drive to the top of the bluff via Summit Road and stand in awe at the sight of the bluffs rising from the prairie.

Over 5 million years of erosion have removed 400 to 800-plus feet of sedimentary rock, and the process continues. Evidence of erosion is visible along the Summit Trails.

| TRAILS & PATHWAYS

The Summit Overlook Trails can be reached on foot via the Saddle Rock Trail or by vehicle via the 1.7-mile-long Summit Road. The South Overlook trail is a relatively flat 0.4-mile (0.64 km) path whereby visitors can view the visitor center and Mitchell Pass from above. The 0.5-mile (0.8 km) North Overlook trail begins with a quick 16% uphill trek before leveling out. This trail has several overlooks to view the North Platte Valley below. The trail’s final 100 yards (91 meters) consists of a 19% downhill grade, with drop-offs on both sides of the path. Hikers on the North Overlook Trail will reach 4,659 feet (1,420 m) above sea level, the highest point on the bluff.

The Bike Path is the only trail available for cyclists and hikers. It begins at the visitor center at the park’s eastern boundary, dropping 50 feet (15 m) in 1.2 miles (1.9 km).

The 0.4-mile (0.64km) Oregon Trail Pathway is a favorite among children. The paved trail begins west of the museum, where visitors can view eroded depressions, or swales, from the original Oregon Trail. There are also three replica-covered Murphy and Conestoga wagons. During the summer, visitors can speak with park rangers dressed in period costumes, discuss the items used on the trails, and learn what life was like traveling along the path. The trail continues uphill at a 13% grade, with the location ending in Mitchell Pass near the William Henry Jackson campsite.

For more experienced hikers looking for a more primitive hike, the South Bluff is an alternative option to the paved trails. Hikers should check in with park rangers at the visitor center before and after a walk at the South Bluff.

The summit of South Bluff is 4,692 feet (1430 meters) above sea level. It is a relatively unspoiled area of the national monument. Visitors often marvel at its geological features, varied botanical interests, and scenic views. South Bluff National Monument consists of sandstone, siltstone, volcanic ash, and limestone, allowing visitors to see and feel the variety of rocks for which the area is known. Each layer can be seen at a distance, and the unspoiled area of the south bluff provides ample opportunity to sit and ponder the immensity of geologic time and beauty.

The National Park Service intends to keep the area as it is, with no modern improvements. South Bluff features three of the five rocks which make up the monument: Dome Rock, Crown Rock, and Sentinel Rock. Because of the soft and highly fragile nature of the Brule clay formation of these steep rocks, it is not permitted to climb them.

The eastern side of South Bluff consists of Dome Rock, its most prominent and most isolated feature. Coyote Pass, a gap between Sentinel and Crown Rocks, is 4,331 feet (1320 meters) above sea level. The famed Mitchell Pass lies between Sentinel Rock and Eagle Rock at the western end of South Bluff.

For everyone’s safety, please stay on the trails. The Saddle Rock Trail and Summit Trails contain soft and crumbly rock. Leaving the trails can be dangerous. If you have small children, it is recommended you use a harness. There are no safety barriers along the paths, with several hundred-foot drops should one slip and fall.

Pets are allowed on the trails but must always be on a leash. Leashes cannot exceed six feet in length. This is for the safety of your pets, the wildlife who call the monument home, and other visitors sharing the trails with you. Pet owners are asked to clean up after their pets as well.

The Prairie Rattlesnake is the most common venomous snake in Western Nebraska and is often found sunbathing on the rocks on warm days. The snake is easily recognizable by its light brown, gray, or dark brown blotchy skin pattern and a distinctive triangular-shaped head with pits between the eyes and lips. Though shy and tends to avoid humans, it will strike if threatened. Snakes can be easily spotted from the trail but can be hidden by vegetation if you are hiking off-trail.

With hikes from easy to strenuous, the Scotts Bluff National Monument has nearly four miles of trails for visitors. Trails are open every day from sunrise to sunset, giving hiking enthusiasts a chance to add their footsteps to the thousands who came before them. The visitors center and Summit Road have seasonal hours. Be sure to check in advance of their times.

The park asks everyone to pack what they take in so others can enjoy the area’s beauty. Park grounds, trails, and picnic areas are open daily from sunrise to sunset. Visitor Center and Summit Road hours vary on season and road conditions.

| CREDITS & RESEARCH