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



The Rooney family establishes a homestead and begins what would become the largest cattle ranch in Colorado history at the eastern base of the hogback in the early 1860s.


Arthur Lakes finds a Tyrannosaurus rex tooth on South Table Mountain in Golden and recognizes it as belonging to a large carnivorous dinosaur. (T. rex was not named by paleontologists until a partial skeleton was unearthed in Montana in 1905).


The first dinosaur bone fossils are collected from what would become the world-famous Morrison Formation of Late Jurassic age. Some of the most iconic dinosaurs now known lived and died in the area now called Dinosaur Ridge, including Stegosaurus, Apatosaurus, Diplodocus, and Allosaurus, long before the Rocky Mountains uplifted. Arthur Lakes, a professor in Golden, led excavations at 15 quarries along the Dakota Hogback in the Morrison area in search of dinosaur fossils.


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


The first Triceratops discovery to be published occurs near present day North Federal Boulevard in Denver. (Two large horns were misidentified as bison horns.)


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


Alameda Parkway is constructed to provide easier access from Denver to Red Rocks Park. Dynamite blasting reveals hundreds of dinosaur footprints, mostly Iguanodon-like tracks, perhaps from Eolambia. Carnivorous theropod tracks were also present.


Otis and Al Rooney build the house that now serves as the Dinosaur Ridge Main Visitor Center Gift Shop.


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

That same year, the Dinosaur Ridge area is nationally recognized for its uniqueness and historical and scientific significance when the Department of the Interior designates the Morrison Fossil Area National Natural Landmark on November 7, 1973.


Council Tree, also known as Inspiration Tree, is placed on the National Register of Historic Places. Ute Mountain Ute tribal Chief Colorow is said to have held councils near the tree in the late 1800s. The ponderosa pine is thought to be 400-500 years old.


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


Governor Richard D. Lamm signs an Executive Order on April 28 establishing the Stegosaurus as Colorado’s state fossil following a 2-year campaign by 4th graders and their teacher Ruth Sawdo at McElwain Elementary School in Thornton.


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


The nonprofit Friends of Dinosaur Ridge (FODR) forms to address increasing concerns regarding the preservation of the site and to offer educational programs on the area’s resources. Articles of Incorporation are filed on April 25.


FODR publishes “A Field Guide to Dinosaur Ridge” authored by paleontologist and UC Denver professor Dr. Martin Lockley.


A large concretion falls out of the road cut on Dinosaur Ridge and cracks upen revealing wood that has almost completely altered to carbon.

The first major paleontological excavation since the Yale dinosaur bone excavations of the late 1870s is performed at the main tracksite. Six parallel dinosaur trackways are revealed on the southern side of the sloping tracksite.


USGS approves the placename, Dinosaur Ridge.

FODR pilots its first summer camp for 10- to-12-year-old students. Two one-week sessions are held.


Construction begins on the Dinosaur Ridge Visitor Center in a historic stone house on West Alameda Parkway, and officially opens on October 22.


FODR completes a stabilization project at the Bone Bed site on the west side of Dinosaur Ridge.


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


The Dan Turner Field Experience Fund is created to assist lower-income schools with the cost of taking field trips to Dinosaur Ridge.


Stabilization of the “Bulges” tracksite is completed on the west side of Dinosaur Ridge.

FODR’s board appoints the organization’s first Executive Director, Joe Tempel.

FODR renovates the historic Rooney barn and moves its administrative offices inside.


Fossil Trace Golf Course opens in Golden and FODR begins hosting tours of the trace fossils at the location now known as Triceratops Trail.


Triceratops Trail is completed adjacent to Fossil Trace Golf Course.


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


Trek Through Time, a small exhibit hall, opens inside the historic barn.

Public traffic along West Alameda Parkway is closed from Rooney Road to HWY-93 across Dinosaur Ridge.


The location of Arthur Lakes’ Quarry 1 is rediscovered about one half mile north of Dinosaur Ridge along HWY-93.

Scientists from Massachusetts Institute of Technology’s EarthTime Project dated volcanic ash layers exposed at Dinosaur Ridge’s road cut. Using the uranium-lead zircon method of dating they found the ash to be 106 million years old.

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 Morrison Fossil Area NNL is expanded to include Triceratops Trail making it the Morrison-Golden Fossil Areas National Natural Landmark.


The Ute Council Tree located near Rooney Road and West Alameda Pkwy is named a Jefferson County Historic Landmark.

The Harvey Family Foundation purchases a Sikh Temple located on the west side of Dinosaur Ridge inside Entrance 1 to Red Rocks Park & Amphitheatre in 2012. The property is given to FODR as a secondary operating location. The Discovery Center opens to the public with a gift shop and exhibit space in 2013.


Dr. Martin Lockley announces the discovery of two trace fossils on Dinosaur Ridge north of the main tracksite. These fossilized “leks” were likely pseudo-nests scraped into soft ground by dinosaurs during courtship.

A Raptor track is identified on Dinosaur Ridge; the first discovered in Colorado and only the second found in North America.


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


Jefferson County, working in conjunction with Friends of Dinosaur Ridge, publishes a Master Plan for Dinosaur Ridge which includes plans for a new Visitor Center.

A greeting kiosk is built near the head of Triceratops Trail adjacent to 6th Avenue east of 19th Street in Golden.

The organization celebrates its 30th year with seven public events and a homecoming extravaganza for 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 opens 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 Jefferson County Democrats) 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 dies 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.”

March 17 the Discovery Center is officially renamed the Martin G. Lockley Discovery Center in a memorial ceremony attended by 150 people including Lockley family members and numerous past and present FODR staff and volunteers. The Master Planning Committee begin plans to remodel the exhibit hall and building.


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