Front Range

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Front Range
Indian Peaks Wilderness.jpg
Front Range Peaks in the Indian Peaks Wilderness
Highest point
PeakGrays Peak
Elevation 14,278 ft (4,352 m)
Coordinates 39°38′02″N105°49′01″W / 39.63389°N 105.81694°W / 39.63389; -105.81694 Coordinates: 39°38′02″N105°49′01″W / 39.63389°N 105.81694°W / 39.63389; -105.81694
Image Wpdms nasa topo front range.jpg
The Front Range (excluding the Laramie Mountains) is shown highlighted on a map of the western U.S.
Country United States
StatesColorado and Wyoming
Parent range Rocky Mountains

The Front Range is a mountain range of the Southern Rocky Mountains of North America located in the central portion of the U.S. State of Colorado, and southeastern portion of the U.S. State of Wyoming. [1] It is the first mountain range encountered as one goes westbound along the 40th parallel north across the Great Plains of North America.


The Front Range runs north-south between Casper, Wyoming and Pueblo, Colorado and rises nearly 10,000 feet above the Great Plains. Longs Peak, Mount Evans, and Pikes Peak are its most prominent peaks, visible from the Interstate 25 corridor. The area is a popular destination for mountain biking, hiking, climbing, and camping during the warmer months and for skiing and snowboarding during winter. Millions of years ago, the present-day Front Range was home to ancient mountain ranges, deserts, beaches, and even oceans. [2]

The name "Front Range" is also applied to the Front Range Urban Corridor, the populated region of Colorado and Wyoming just east of the mountain range and extending from Cheyenne, Wyoming south to Pueblo, Colorado. This urban corridor benefits from the weather-moderating effect of the Front Range mountains, which help block prevailing storms.


Pikes Peak and Garden of the Gods. Ppgog.JPG
Pikes Peak and Garden of the Gods.
Sandstone slabs along the eastern edge of the Front Range Fountain Valley Trail (5974714678).jpg
Sandstone slabs along the eastern edge of the Front Range

Pikes Peak Granite

About 1 billion years ago, the earth was producing massive amounts of molten rock that would one day amalgamate, drift together and combine, to ultimately form modern continents. In the Colorado region, this molten rock spewed and cooled, forming what we now know as the Precambrian Pikes Peak Granite. Over the next 500 million years, little is known about changes in the sedimentation (sediment deposition) after the granite was produced. However, at about 500–300 million years ago, the region began to sink and sediments began to deposit in the newly formed accommodation space. Eroded granite produced sand particles that began to form strata, layers of sediment, in the sinking basin. Sedimentation would continue to take place until about 300 million years ago. [2]

Fountain formation

Around 300 million years ago, the sinking suddenly reversed, and the sediment-covered granite began to uplift, giving rise to the Ancestral Rocky Mountains. Over the next 150 million years, during uplift the mountains would continue to erode and cover themselves in their own sediment. Wind, gravity, rainwater, snow, and ice-melt supplied rivers that ultimately carved through the granite mountains and eventually led to their end. The sediment from these mountains lies in the Fountain Formation today. Red Rocks Amphitheatre outside of Denver, Colorado, is actually set into the Fountain Formation. [2]

Lyons Sandstone

At 280 million years ago, sea levels were low and present-day Colorado was part of the super-continent Pangaea. Sand deserts covered most of the area spreading as dunes seen in the rock record, known today as the Lyons Sandstone. These dunes appear to be cross-bedded and show various fossil footprints and leaf imprints in many of the strata making up the section. [2]

Lykins Formation

30 million years later, the sediment deposition was still taking place with the introduction of the Lykins Formation. This formation can be best attributed to its wavy layers of muddy limestone and signs of stromatolites that thrived in a smelly tidal flat at present-day Colorado. 250 million years ago, the Ancestral Rockies were burying themselves while the shoreline was present during the break-up of Pangaea. This formation began right after Earth's largest extinction 251 million years ago at the PermianTriassic Boundary. Ninety percent of the planet's marine life was destroyed and a great deal on land as well. [2]

Morrison Formation

After 100 million years of deposition, a new environment brought rise to a new formation, the sandstone Morrison Formation. The Morrison Formation contains some of the best fossils of the Late Jurassic. It is especially known for its sauropod tracks and sauropod bones among other dinosaur fossils. As identified by the fossil record, the environment was filled with various types of vegetation such as ferns and Zamites . [2] While this time period boasts many types of plants, grass had not yet evolved. [2]

Dakota Sandstone

The Dakota Sandstone, which was deposited 100 million years ago towards Colorado's eastern coast, shows evidence of ferns, and dinosaur tracks. Sheets of ripple marks can be seen on some of the strata, confirming the shallow-sea environment. [2]

Pierre Shale

Over the next 30 million years, the region was finally taken over by a deep sea, the Cretaceous Western Interior Seaway, and deposited mass amounts of shale over the area known as the Pierre Shale. Both the thick section of shale and the marine life fossils found (ammonites and skeletons of fish and such marine reptiles as mosasaurs, plesiosaurs, and extinct species of sea turtles, along with rare dinosaur and bird remains). Colorado eventually drained from being at the bottom of an ocean to land again, giving yield to another fossiliferous rock layer, the Denver Formation. At about 68 million years ago, the Front Range began to rise again due to the Laramide Orogeny in the west. [2]

Denver Formation

Front Range near Estes Park, Colorado. Mmtn.JPG
Front Range near Estes Park, Colorado.

The Denver Formation contained fossils and bones from dinosaurs like Tyrannosaurus rex and Triceratops. While the forests of vegetation, dinosaurs, and other organisms thrived, their reign would come to an end at the Cretaceous–Paleogene boundary (which is formerly known as the K-T boundary). In an instant, millions of species were obliterated from a meteor impact in Mexico's Yucatán Peninsula. While this extinction led to the demise of the dinosaurs and other organisms, some life did prevail to repopulate the earth as it recovered from this tremendous disaster. The uplifted Front Range continued to constantly erode and, by 40 million years ago, the range was once again buried in its own rubble. [2]

Castle Rock Conglomerate

Suddenly, 37 million years ago, a great volcanic eruption took place in the Collegiate Range and covered the landscape in molten hot ash that instantly torched and consumed everything across the landscape. An entire lush environment was capped in a matter of minutes with 20 feet of extremely resistant rock, rhyolite. However, as seen before, life rebounds, and after a few million years mass floods cut through the rhyolite and eroded much of it as plants and animals began to recolonize the landscape. The mass flooding and erosion of the volcanic rock gave way to the Castle Rock Conglomerate that can be found in the Front Range. [2]

Quaternary deposits

Eventually, at about 10 million years ago, the Front Range began to rise up again and the resistant granite in the heart of the mountains thrust upwards and stood tall, while the weaker sediments deposited above it eroded away. As the Front Range rose, streams and recent (16,000 years ago) glaciations during the Quaternary age literally unburied the range by cutting through the weaker sediment and giving rise to the granitic peaks present today. [2] This was the last step in forming the present-day geologic sequence and history of today's Front Range. [2]

Mountains from westlands.jpg
The Front Range as viewed from Greenwood Village south of Denver, Mount Evans is on the far right

Prominent peaks

The Front Range includes the highest peaks along the eastern edge of the Rockies. The highest mountain peak in the Front Range is Grays Peak. Other notable mountains include Torreys Peak, Mount Evans, Longs Peak, Pikes Peak, and Mount Bierstadt.

Longs Peak Longs peak.JPG
Longs Peak
Pikes Peak Pike's Peak4.jpg
Pikes Peak
Mount Evans Mevans.JPG
Mount Evans
The 20 Mountain Peaks of the Front Range With At Least 500 Meters of Topographic Prominence
Rank Mountain Peak Subrange Elevation Prominence Isolation
1 Grays Peak [3] NGS Front Range14,278 ft
4352 m
2,770 ft
844 m
25 mi
40.3 km
2 Mount Evans NGS Front Range14,265 ft
4348 m
2,769 ft
844 m
9.79 mi
15.76 km
3 Longs Peak NGS Front Range14,259 ft
4346 m
2,940 ft
896 m
43.6 mi
70.2 km
4 Pikes Peak NGS Pikes Peak Massif 14,115 ft
4302 m
5,530 ft
1686 m
60.8 mi
97.8 km
5 Mount Silverheels NGS PB Front Range13,829 ft
4215 m
2,283 ft
696 m
5.48 mi
8.82 km
6Bald Mountain [4] PB Front Range13,690 ft
4173 m
2,099 ft
640 m
7.51 mi
12.09 km
7 Bard Peak [4] PB Front Range13,647 ft
4159 m
1,701 ft
518 m
5.43 mi
8.74 km
8 Hagues Peak NGS PB Mummy Range 13,573 ft
4137 m
2,420 ft
738 m
15.92 mi
25.6 km
9 North Arapaho Peak [4] PB Indian Peaks PB 13,508 ft
4117 m
1,665 ft
507 m
15.4 mi
24.8 km
10 Parry Peak [4] Front Range13,397 ft
4083 m
1,731 ft
528 m
9.46 mi
15.22 km
11 Mount Richthofen [4] PB Front Range12,945 ft
3946 m
2,680 ft
817 m
9.66 mi
15.54 km
12 Specimen Mountain [4] PB Front Range12,494 ft
3808 m
1,731 ft
528 m
4.86 mi
7.82 km
13 Bison Peak NGS PB Tarryall Mountains PB 12,432 ft
3789 m
2,451 ft
747 m
19.14 mi
30.8 km
14 Waugh Mountain [4] PB South Park Hills PB 11,716 ft
3571 m
2,330 ft
710 m
20 mi
32.2 km
15 Black Mountain NGS PB South Park Hills PB 11,649 ft
3551 m
2,234 ft
681 m
8.03 mi
12.92 km
16 Williams Peak NGS PB South Williams Fork Mountains PB 11,620 ft
3542 m
2,049 ft
625 m
10.79 mi
17.37 km
17Puma Peak [4] PB South Park Hills PB 11,575 ft
3528 m
2,260 ft
689 m
7.44 mi
11.97 km
18 Thirtynine Mile Mountain [4] PB South Park Hills PB 11,553 ft
3521 m
2,088 ft
636 m
10.61 mi
17.08 km
19 Twin Sisters Peaks [4] PB Front Range11,433 ft
3485 m
2,328 ft
710 m
4.36 mi
7.01 km
20 South Bald Mountain Laramie Mountains 11,007 ft
3355 m
1,844 ft
562 m
13.66 mi
22 km


The main interstate highways that run through the Front Range are Interstate 70, which crosses west of Denver, Colorado, and Interstate 80, which crosses near Laramie, Wyoming. U.S. Route 34 travels through the mountains near Loveland, Colorado, although this route is typically closed from October to May. [5] U.S. Route 24 travels through the southern Front Range west of Colorado Springs, eventually connecting with I-70 west of Vail, Colorado.

Along with the roads that run through the Front Range, the Union Pacific Railroad operates two rail lines through the mountains. The first Overland Route, transiting southern Wyoming, runs parallel to I-80 for much of its way. The second is the former Denver & Rio Grande Western Railroad Moffat Route, which runs parallel to the Colorado River and through the 6.5-mile-long Moffat Tunnel. Originally the Denver and Salt Lake Railway, the former Rio Grande is used for freight by both Union Pacific and BNSF, and it is also used by Amtrak's California Zephyr and Winter Park Express .

See also

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Dakota Formation

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The Denver Formation is a geological formation that is present within the central part of the Denver Basin that underlies the Denver, Colorado, area. It ranges in age from latest Cretaceous (Maastrichtian) to early Paleocene, and includes sediments that were deposited before, during and after the Cretaceous-Paleogene boundary event.

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Prehistory of Colorado provides an overview of the activities that occurred prior to Colorado's recorded history. Colorado experienced cataclysmic geological events over billions of years, which shaped the land and resulted in diverse ecosystems. The ecosystems included several ice ages, tropical oceans, and a massive volcanic eruption. Then, ancient layers of earth rose to become the Rocky Mountains.

Arapahoe Formation

The Arapahoe Formation is a geological formation of latest Cretaceous (Maastrichtian) age that is present within the Denver Basin that underlies the Denver, Colorado, area. The formation includes fossil leaves and dinosaur remains, although none of the latter have yet been referred to a specific genus. It also includes aquifers that are important sources of water for the area.

Split Rock (Wyoming) United States historic place

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The geology of Colorado was assembled from island arcs accreted onto the edge of the ancient Wyoming Craton. The Sonoma orogeny uplifted the ancestral Rocky Mountains in parallel with the diversification of multicellular life. Shallow seas covered the regions, followed by the uplift current Rocky Mountains and intense volcanic activity. Colorado has thick sedimentary sequences with oil, gas and coal deposits, as well as base metals and other minerals.


  1. "GNIS Feature Search". Archived from the original on 2012-07-14. Retrieved 2010-05-13. | U.S. Geological Survey confirms that the Laramie Mountains(range) are the northern extent of the Front Range.
  2. 1 2 3 4 5 6 7 8 9 10 11 12 13 Johnson, Kirk R.; et al. (2006). Ancient Denvers. Fulcrum Publishing. ISBN   978-1-55591-554-4.
  3. The summit of Grays Peak is the highest point on the Continental Divide of North America.
  4. 1 2 3 4 5 6 7 8 9 10 The elevation of this summit has been converted from the National Geodetic Vertical Datum of 1929 (NGVD 29) to the North American Vertical Datum of 1988 (NAVD 88). National Geodetic Survey Archived 2011-10-19 at the Wayback Machine
  5. "Road Status Report - Rocky Mountain National Park (U.S. National Park Service)". Archived from the original on 8 February 2019. Retrieved 8 January 2020.

Further reading