History & Discoveries

Dinosaur Ridge: A Brief History

For centuries, Indigenous peoples lived and traveled across the land now known as Colorado’s Front Range, including the long hogback ridge extending between the foothills of the Rocky Mountains and the grasslands of the Great Plains. In particular, members of the Ute Mountain Ute Tribe hunted animals and gathered seasonal plants in this fertile land. It is likely they came across fossils of extinct plants and animals and recognized the differences from the wildlife they were encountering themselves.

In 1876, Arthur Lakes, a professor at Jarvis Hall (which would become the Colorado School of Mines) in Golden, identified many fossils along the west side of the Dakota Hogback. This hogback would eventually be named Dinosaur Ridge. Sending the fossils to Yale Peabody Museum c/o Professor Othniel Charles Marsh, the paleontologist named many well-known dinosaurs from these remains. These included Apatosaurus, Stegosaurus (the Colorado State Fossil), Allosaurus, turtle fossils, and more. These specimens represent animals that lived 150 million years ago in the Late Jurassic Period, also known as the “Age of Giants.”

In 1937, during the construction of West Alameda Parkway, dinosaur tracks were uncovered on the east side of Dinosaur Ridge in the 100-million-year-old rocks of the Dakota Group, representing the Early Cretaceous Period. These tracks are those of duck-billed herbivores and ostrich-like carnivorous dinosaurs. Recent research has revealed that these tracks represent only a small number of the extensive track-bearing beds of the Dakota Group, which can be traced from Boulder, Colorado, to northern New Mexico. Because these strata represent the shoreline sediments of an ancient seaway that was frequently trampled by dinosaurs, these beds have been dubbed the “Dinosaur Freeway.”

Land Acknowledgement Statement

The original caretakers of the lands we now call Jefferson County Open Space Parks include the Tabeguache and Moghwachi bands of the Ute Nation, the Arapaho and Cheyenne Tribes, and other Indigenous Peoples. Their knowledge, resilience, and cultural and spiritual ties to these lands inspire us to continue their legacy by practicing informed stewardship, providing equitable access, teaching sound outdoor ethics, and treating nature and humanity with respect.

A Timeline of Dinosaur Ridge


Nearby Rooney Ranch was homesteaded in the early 1860s.


T. rex tooth was found nearby on South Table Mountain and recognized as that of a large carnivorous dinosaur. (T. rex was not formally named by paleontologists until a partial skeleton was unearthed in Montana in 1905).


First material ever collected from the world-famous Morrison Formation of Late Jurassic age was found at Dinosaur Ridge. Some of the best-known dinosaurs were found here, including Stegosaurus, Apatosaurus, Diplodocus, and Allosaurus. Fifteen quarries were opened along the Dakota Hogback in the Morrison area in search of these fossils.


Otis Rooney discovered the first horned dinosaur remains from a gulch near the intersection of the present Alameda Parkway, Bear Creek Boulevard, and West Jewell Avenue.


First Triceratops discovery to be published was found near present day North Federal Boulevard in Denver. (The two larger of the three horns were found and were originally thought to be bison horns.)


Arthur Lakes discovered the first dinosaur footprints in Colorado along the Front Range near Colorado Springs.


Alameda Parkway was constructed to provide access to Red Rocks Park. Workers discovered hundreds of dinosaur footprints. These were found to include mostly Iguanodon-like footprints, perhaps from Eolambia. Carnivorous theropod tracks were also present.


Otis and Al Rooney built the house that is now the Dinosaur Ridge Main Visitor Center Gift Shop.


Jefferson County Open Space purchased 69 acres known as the “Nelson Hogback.” This was the first parcel of many that now comprises the 2,461-acre Matthews/Winters Park where Dinosaur Ridge is located.

The Dinosaur Ridge area was recognized for its uniqueness as well as its historical and scientific significance when it was designated the Morrison Fossil Area National Natural Landmark by the National Park Service on November 7, 1973.


Council Tree, also known as Inspiration Tree, which still grows at the foot of Dinosaur Ridge was placed on the National Register of Historic Places. Ute Mountain Ute tribal chief Colorow held councils there in the late 1800s. The ponderosa pine is thought to be between 400-500 years old.


Rooney Ranch (Jefferson County’s oldest ranch) was designated a Jefferson County Landmark.


Kickoff meeting “Re. Development and Protection of Colorado’s Dinosaur Resources” (the origin of Friends of Dinosaur Ridge) was held at the University of Colorado at Denver.


The Friends of Dinosaur Ridge formed to address increasing concerns regarding the preservation of the site and to offer educational programs on the area’s resources.


Dinosaur Ridge published “A Field Guide to Dinosaur Ridge.”


A concretion fell out of Dinosaur Ridge south hillside revealing decayed wood almost completely altered to carbon.


First major paleontological excavation since the Yale dinosaur bone excavations of the late 1870s took place on Dinosaur Ridge. Six parallel trackways were revealed.


The placename, Dinosaur Ridge, was approved by the USGS.

Dinosaur Ridge piloted its first summer camp for 10- to 12-year-old students. Two one-week sessions were held.


Construction began on the Dinosaur Ridge Visitor Center in the historic house on Dinosaur Ridge’s Main Visitor Center property. Visitor Center officially opened on October 22, 1996.


Dinosaur Ridge completed the Bone Site stabilization project.


The main tracksite pedestrian ramp and seating area were completed on Dinosaur Ridge.


The Dan Turner Field Experience Fund was created to assist lower-income school children with the cost of visiting Dinosaur Ridge.


Stabilization of Brontosaur Bulges was completed on west side of Dinosaur Ridge.


Friends of Dinosaur Ridge’s first executive director, Joe Tempel, was appointed.


Dinosaur Ridge renovated the historic barn and moved its administrative offices there.


Fossil Trace Golf Course opened and FoDR began hosting tours of the fossils and tracks at the location that became known as Triceratops Trail.


Triceratops Trail was completed at Fossil Trace Golf Course.


Dinosaur Ridge was selected by the Denver Post as one of the “Top 10 Things to Do Before You Die.”


Trek Through Time, our indoor exhibit hall, opened in the historic barn.


Alameda Parkway was restricted to vehicular traffic.


The location of Arthur Lakes’ lost Quarry 1 was rediscovered ~0.5 mile north of Dinosaur Ridge along County Road 93.


EarthTime Project, scientists from Massachusetts Institute of Technology, dated three separate layers of ash exposed at Dinosaur Ridge’s “Ash Beds” using the uranium-lead zircon method of dating.


Friends of Dinosaur Ridge, the Morrison Natural History Museum, and Triebold Paleontology, operator of the Rocky Mountain Dinosaur Resource Center in Woodland Park, formed the Dinosaur Corridor.


The Ute Council Tree was named a Jefferson County Historic Landmark.


The Dinosaur Ridge Martin G. Lockley Discovery Center opened on the west side of Dinosaur Ridge.


Dr. Martin Lockley announced the discovery of two newly-recognized ichnofossils at Dinosaur Ridge. These “leks,” were pseudo-nests constructed by dinosaurs during courtship.


A new Raptor track was discovered at Dinosaur Ridge; the first discovered in Colorado and only the second found in North America.


Program evaluation staff capacity is formally added to our education department.


Dinosaur Ridge is formally appointed as a state-approved curatorial fossil repository.


Jefferson County, working in conjunction with Friends of Dinosaur Ridge, publishes a Master Plan for Dinosaur Ridge.


A greeting kiosk is built near the head of Triceratops Trail adjacent to Route 93 in Golden.


The organization celebrates its 30th year with a 7-events-in-4-days homecoming extravaganza for our co-founders and longtime supporters.


Dinosaur Ridge shuts down all tour, program, and gift shop operations due to the COVID-19 pandemic. Other social distancing and capacity restrictions disrupt organizational life for well over a year.


Dinosaur Ridge surpasses 250,000 visitors for the first time, fueled partly by walkers and cyclists seeking outdoor activities during the pandemic; summer camps also surpass previous record attendance.


A stylized Eolambia statue crafted by local artists Pat Madison and Jim Dickson is placed at Crocodile Creek on Dinosaur Ridge, and a donated Triceratops statue is placed at the Main Visitor Center.


April 27, the long-awaited stairway and viewing platform at Crocodile Creek opened to the public. The 25-foot climb enables visitors to closely view a dinosaur trackway difficult to see from the roadway below.

May 22, Governor Jared Polis holds a signing ceremony at the Dinosaur Ridge Main Tracksite for SB123-145 to make the Stegosaurus State Fossil License Plate official. State Senators Jessie Danielson, Lisa Cutter and Representatives Tammy Story and Briana Titone all of Jefferson County co-sponsored the bill.

November 7 marks the 50th anniversary of the Morrison Fossil Area National Natural Landmark (NNL) designation, which includes Dinosaur Ridge, by the Department of the Interior’s National Park Service.

November 25, Dinosaur Ridge co-founder and world renown paleontologist Dr. Martin G. Lockley passes away at the age of 73.


January 1, the Stegosaurus State Fossil License Plate is available for Colorado drivers. Designed by local artist Julia Williams, the plate features a Stegosaurus image and a setting sun behind the Rocky Mountains and the tagline “Protect Our Fossils.”

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