Trail Description

NEW - Add Trail Comments & Share Photos

140 million years ago the Rabbit Mountain area marked the western shoreline of a massive inland sea that stretched from the Gulf of Mexico to the Hudson Bay. It was a tropical lowland covered by rivers, swamps, and lagoons. This sea retreated approximately 65 million years ago when tectonic forces pulled upon the earth’s crust, resulting in a western uplift that gave rise to the Rocky Mountains. The uplift’s ripples caused rocks to compress and bulge at its base, creating anticlines - or convex folds on the earth’s surface. As the bulging anticline’s softer sediments eroded, only hard ridges - known as Hogbacks - remained from the previously rounded hilltops.

Unique to Rabbit Mountain is its position three miles east of similar anticline formations along Colorado’s northern Front Range communities. The complex movements of two faults in the area pushed these eroding anticlines east, and with a rare orientation: their steepest sides face east, and gentler slopes to the west. This unusual location and orientation make it a natural landmark visible from three counties.

The Little Thompson Overlook Trail traces the east face of one such hogback to an elevated outcrop with excellent views of the Eastern Plains and Little Thompson River below. This easy out-and-back is well suited for those with families or limited time. Hikers, runners, cyclists and winter recreationalists will enjoy mild grades, favorable trail conditions and good wildlife viewing opportunities throughout.

----

The trail heads northeast from the parking area on a winding course to the Little Thompson Overlook Trail junction (.5 miles : 5,712’). Bear left. The trail curls northeast to the back side of a steep-faced hogback. The Little Thompson River flows below, framed by another row of hogbacks to the east; take a moment to examine these exaggerated anticline formations as you progress. The Little Thompson River’s riparian corridor is densely lined by cottonwood and willow, which stand out in an otherwise expansive tract of open space and sparsely treed hilltops. The hillsides around you are dotted with sage, yarrow, cacti, yucca and a medley of summer wildflowers.

The trail rises nominally along the hogback’s contours to its apex (1.15 miles : 5,888’), from which it drops gently to its terminus at the Little Thompson Overlook (1.45 miles : 5,802’). Here you may scramble about a cluster of boulders for prime vantages and viewpoints. Prairie Rattlesnakes are common to the Rabbit Mountain area, and favor terrain found along the Little Thompson Overlook Trail. While seldom seen and encounters are rare, be cognizant of their presence and never place your hands or feet where you cannot see them.

GPS Coordinates - DATUM WGS84

• N40 14.798 W105 13.420 - Rabbit Mountain Trailhead

• N40 14.977 W105 13.085 - .5 miles : Littel Thompson Overlook Trail junction

• N40 15.365 W105 13.236 - 1.0 mile mark

• N40 15.643 W105 13.219 - 1.45 miles : Overlook - end of trail

Worth Noting

• Late afternoon visitors will enjoy exceptional lighting of nearby hogbacks and the Eastern Plains.



• Rabbit Mountain stands along a divisive uplift between the Saint Vrain drainage basin (south) and Big Thompson drainage basin (north). Here the Great Plains meet the Rocky Mountain upslope, a rich ecological juxtaposition that brings animal communities together from each - most notably white tail deer and mule deer - an uncommon occurrence in Colorado. Coyote, fox, rabbit, raptors and rattlesnakes also call this area home.



• The rich hills and recognizable buttes of Rabbit Mountain have been used by ancient peoples dating back over 5,000 years. As indigenous Indians were displaced by western settlers seeking gold, the land became an agricultural mecca for homesteaders in the area. Eventually, the granddaughter of former owner and forest ranger Jack Moomaw sold the land to Boulder County in 1984.



• Fault movements in the Rabbit Mountain area have cracked rock under-layers, freeing water trapped beneath the surface to rise. There are seven natural springs in the Rabbit Mountain area.

Directions to Trailhead

The Rabbit Mountain Trailhead is located 2 miles north of Highway 66 on N. 53rd Street.

From Boulder:
Head north on Highway 36 out of town towards Lyons. Highway 36 will dead end into Highway 66. Turn right on Highway 66 and continue for about 1 mile. Turn left into N. 53rd Street and follow it 2 miles until you see the Rabbit Mountain sign and parking lot on the right.

Contact Information

Boulder County Parks & Open Space
5201 St. Vrain Road
Longmont, Colorado 80503
Phone: 303.678.6200
Fax: 303.678.6180
www.co.boulder.co.us/openspace