Flattop Mountain (Mount Zirkel Wilderness)

Flattop Mountain (Mount Zirkel Wilderness)

Page Type Page Type: Mountain/Rock
Location Lat/Lon: 40.80653°N / 106.63536°W
Additional Information County: Routt
Activities Activities: Hiking, Mountaineering
Seasons Season: Summer, Fall
Additional Information Elevation: 12118 ft / 3694 m
Sign the Climber's Log

Park Range/Mount Zirkel Wilderness Overview

Flattop Mountains expansive flat summit regionFlattop Mountain's expansive summit. Big Agnes Mountain and Mount Zirkel in the distance.
The Park Range is the northern most section of the Greater Park Range. The Greater Park Range is a discontinuous uplift consisting of the Sierra Madre Mountains, the Park Range, the Gore Range, and the Tenmile/Mosquito Mountains. It is bisected by Rabbit Ears Pass, Gore Canyon, Tenmile Canyon, and the Continental Divide on the perpendicular denying it the continuity of the Sawatch or the Sangre de Cristos.

The Park Range carries the Continental Divide into Colorado from the Wyoming border. Geologically it represents one of the original eroded uplifts of the Laramide orogeny (the mountain building event that produced the Rocky Mountains of Colorado). Between 70 and 65 million years ago the Rocky Mountains were first thrust upward. An intermittent pause in this uplift allowed the first mountains to be reduced to a level plain by the forces of erosion. The overlaying sedimentary rocks (up to two miles worth) were stripped away leaving the ancient core of this mountain range exposed. This ancient erosional surface gives Flattop Mountain its distinctive Flat topped profile. This ancient erosional surface can be seen on many other mountains in the state (especially in Rocky Mountain National Park) A subsequent resumption of the uplift then hoisted this flat surface to over 12,000 ft. in the vicinity of Flattop Mountain. The rock in this area consists of layered metamorphic rocks, such as felsic gneiss and amphphibolite, intruded by a 1.7 billion year old red granite near Mount Zirkel. 15,000 years ago Pleistocene glaciation sculpted these hard basement rocks to produce beautiful glacial canyons, cliffs, and spires. The evidence of glaciation is everywhere in the Park Range and several permanent snowfields are still found to the north of Red Dirt Pass.

Today the Park Range has three mountains that top 12,000 ft. Mount Zirkel, Flattop Mountain, and Big Agnes Mountain. This area gets ample winter snowfall and summer rain. Combined with fertile soils this makes the area very lush with some of the best wildflower displays seen in the state. Abundant wildlife flourishes in the valleys and on the ridges. On every visit I have seen moose, bighorn sheep, and deer.

The pristine beauty of the Park Range has been challenged by two recent natural disasters in the vicinity of the Slavonia Trailhead. In October 1997 a downslope windstorm blew down over 20,000 acres of old growth forest. These winds in excess of 100 miles per hour out of the east resulted in a huge tangle of downed timber. A second catastrophe occurred in August 2002 when the Hinman Fire scorched the same area. The wilderness has recovered well but the remnants of these events are evident as one hikes the Gold Creek Trail.

The majority of the Park Range is protected within the confines of the Mount Zirkel Wilderness. This is one of the five original Colorado wilderness areas designated by Congress in 1964. The wilderness protects 159,935 acres and the headwaters of the Elk and Encampment rivers. The area feels a bit different then many of Colorado's more southern wilderness areas. Perhaps it is the northern location; so close to the more expansive and wild wilderness areas of Wyoming.
Gilpin LakeGilpin Lake. Mount Zirkel Wilderness.
Flattop Mountain and Little Elephant Head flowersLittle Elephant Head flowers near the origin of Gold Creek. Flattop Mountain is on the left.

Flattop Mountain Overview

Flattop Mountain from Gold LakeFlattop Mountain from Gold Lake.
Flattop Mountain is the second highest mountain in the Park Range. It is 12,118 ft tall and rises 578 feet from Red Dirt Pass which connects it to Mount Zirkel. Flattop Mountain resides on the Continental Divide and is the sixth mountain the Continental Divide crosses on its march south through Colorado. It is appropriately named as its expansive summit region is reminiscent of the deck of an aircraft carrier, it is a massive mountain. Despite its flat upper reaches Flatttop Mountain's flanks are precipitous, and rise from the dramatic U shaped glacial valley of Gold Creek. Viewed from near Gold Lake Flattop Mountain is dramatic and beautiful. The western edge of the summit sports a lofty spire that is startling from down valley.

Flattop Mountain offers a variety of routes and is easily accessed from the Red Dirt Pass or Ute Pass trails. There are also more direct options. From Red Dirt Pass Flattop Mountain can be combined with Mount Zirkel. As a one day trip from the trailhead this would make for a very long day. It also makes an ideal destination of its own and all routes are offer 13+ miles roundtrip.

The summit views from Flattop Mountain are spectacular. It is an ideal location to preview or review climbs of Big Agnes Mountain and Mount Zirkel. To the north one can see far into Wyoming. To the south the eleveners of the Park Range march of to the south and Lost Ranger Peak and the Dome appear prominently. To the east the vast pastoral expanse of North Park is visible far below. Solitude is almost guaranteed.

Authors notes on Flattop Mountain

Sopris on Flattop Mountain s summitMy dog Sopris on the summit of Flattop Mountain.
I first visited the Mount Zirkel Wilderness on August 21, 2010 on a climb of Mount Zirkel. This represented a blitz of a hike as I drove from Denver at 2am, hiked the mountain, and then drove back all on one spectacular long day. Two weeks later I did the same thing and climbed Big Agnes Mountain. These mountains are awesomely picturesque and jagged. They are among two of my favorite mountains in the whole of Colorado. It is an area that can easily become addictive.

When summer 2011 rolled around I was aching to get back to the beauty of the Mount Zirkel Wilderness. I first attempted to climb Flattop Mountain from the Slavonia Trailhead via the Gold Creek Trail on July 24, 2011. The incredible snowfall and ample rains of 2011 produced conditions I have never encountered in late July. Gold Creek, which at the time required a fording of the creek a mile from the trailhead; was a raging, frothing, runoff swollen monster of a creek. Whitewater over scattered boulders. I balked. I forsaw bad things carrying my dogs across those frigid fast moving waters. I turned back and ascended the Gilpin Lake Trail to Gilpin Lake, making a frigid fording of a slightly less scary Gilpin Creek along the way. Gilpin Lake was still frozen and the entire basin still had a deep blanket of snow. I climbed up to 11,500 ft on the ridge that runs south from Mount Zirkel where I could view Flattop Mountain and the snowy Gold Creek Basin. I would return and try again.

On September 4th, 2011 I returned and by this time most of the snow was melted. The Forest Service had installed a single log bridge across Gold Creek where I had balked before. I had a perfect beautiful day and found an interesting direct route up Flattop Mountain via a very steep grass gully on the west face of Flattop Mountain. On the summit I encountered two bighorn sheep. I lounged and gazed back on Big Agnes and Mount Zirkel. And I appreciated this mountain for what it gave me.

This is the first mountain I have submitted to SummitPost in several years.


Camping is available along the Gold, Giplin, and Mica Basin Trails. Camping is restricted in the vicinity of Gold Lake, Gilpin Lake, and Three Island Lake. The best camping for an ascent of Flattop Mountain with an option for Mount Zirkel would be in upper Gold Basin. There are numerous flat areas with wildflower strewn meadows that would make ideal backpacking destinations.
Flattop Mountain Gold Creek RouteGoogle Earth view of Flattop Mountains Gold Creek Route.

External Links

NOAA Weather Point Forecast for Flattop Mountain.

USFS link for Routt National Forest.


USDA Forest Service
Medicine Bow-Routt
National Forests,
Thunder Basin
National Grassland
2468 Jackson Street
Laramie, WY 82070

Telephone for the
Hearing Impaired



Children refers to the set of objects that logically fall under a given object. For example, the Aconcagua mountain page is a child of the 'Aconcagua Group' and the 'Seven Summits.' The Aconcagua mountain itself has many routes, photos, and trip reports as children.