Bitterbrush Trail to Nelson Loop, Hall Ranch, Boulder - Denver - Golden - Fort Collins - Lyons, Colorado

Bitterbrush Trail to Nelson Loop - 9.4 miles

Hall Ranch

The Bitterbrush Trail and Nelson Loop form a 9.4 mile route through Hall Ranch

The Bitterbrush Trail and Nelson Loop form a 9.4 mile route through Hall Ranch

Round-Trip Length: 9.4 miles
Start-End Elevation: 5,521' - 6,703' (max elevation)
Elevation Change: +1,182' net elevation gain (+1,450' total roundtrip elevation gain)
Skill Level: Moderate
Dogs Allowed: No
Bikes Allowed: Yes
Horses Allowed: Yes
Related Trails:

Bitterbrush Trail to Nelson Loop - 9.4 Miles Round-Trip

Hall Ranch is compelling for its colorful mesas, spacious meadows and rich wildlife. The Bitterbrush Trail and Nelson Loop Trail form a 9.4 mile lollipop loop through rolling hills and elevated meadows in the heart of Hall Ranch.

Trails at Hall Ranch can be muddy, especially after heavy rain and during the spring thaw. Trail conditions are posted at the trailhead. BIkers are advised to stay off trails when muddy to expedite recovery and reduce rutting:

Trail Map | Photo Gallery

The Bitterbrush Trail rolls gently through open grassland for .7 miles, then climbs steeply up rugged, tightly-wound switchbacks. Hikers and runners should make room for cyclists on these quick turns.

The trail levels on a high ridge overlooking an expansive meadow (2.0 miles : 6,151'). This area supports a large prairie dog village, a good place to see coyote, badger, rattlesnakes and raptors.

The Bitterbrush drops sharply to the Antelope Trail split (2.2 miles: 6,089'), and moderates on a rolling course for 1.35 miles to the Nelson Loop Trail junction (3.55 miles: 6,407').

This attractive 2.3 mile loop moves easily through intervals of high open space, thick pine forest and rocky outcrops. Deer are ubiquitous, while rabbit, coyote and fox are also fairly common.

The Nelson Loop gains only 360' in total elevation; travel clockwise for a quicker route to its apex, or counter-clockwise on a more leisurely grade. Both directions offer panoramas across the upper meadows toward Mt Meeker and Longs Peak.

Approximately half-way around, the Nelson Loop connects with the Nighthawk Trail at its highest point (6,703'). The Nighthawk Trail offers a compelling, bike-free alternative route back to the parking lot.

About Hall Ranch

This part of Colorado once marked the western shoreline of a massive inland sea that stretched from the Gulf of Mexico to the Hudson Bay. The inland sea surged and retreated periodically, depositing and compressing sedimentary layers many times over the millennia. Tectonic forces related to the Rocky Mountain uplift rippled east, forcing rock layers to bulge along the plains and exposing them to various forms of erosion.

260 million years ago windblown particles from coastal dunes added to this complex sedimentary mix, creating a hard quartz sandstone called the Lyons Formation. The Lyons Formation has a distinct salmon-red hue for which the iconic mesas of Hall Ranch are known.

Hall Ranch ranges from 5,440' - 6,820' and supports a variety of distinct ecosystems: grasslands, shrublands, ponderosa-pinyon woodlands, Douglass fir forests, riparian corridors and canyons.

Bluestem, New Mexico feathergrass, and western wheatgrass fill meadows, while durable shrubs such as prickly pear cactus, wax current, yucca, and bitterbrush occupy drier, rockier soil beds. Ponderosa, pinyon, and juniper dot the hillsides, naturally spaced apart to maintain a healthy fire cycle. Fir and lodgepole can be found in denser concentrations at higher elevations on the higher, west side of Hall Ranch.

These varied ecosystems overlap in a relatively small space, attracting a wide range of wildlife that includes rattlesnakes, prairie dog, skunk, badger, fox, coyote, turkey, deer, elk, bear, and mountain lion. Bighorn sheep are known to follow winter migration routes through the high, rugged cliffs in the northwest corner of Hall Ranch. Even a short hike through Hall Ranch will expose you to many of these ecotones and inhabitants.

Hall Ranch was first homesteaded by Richard Clark in 1890, and since more than 20 families have lived in the area prospecting, farming, or quarrying sandstone. The Nelson family purchased this land in 1922, and later sold to Hallyn and June Hall in the 1940s. The Nelson Loop Trail circles historic Nelson Ranch in the Antelope Park area, whose grain silo and aging homestead still remain. Several spurs leads off the main trail to the site.

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Interactive GPS Topo Map

Key GPS Coordinates - DATUM WGS84

  • N40 12.730 W105 17.365 — 0.0 miles : Bitterbrush Trailhead at Hall Ranch
  • N40 12.604 W105 18.136 — .7 miles : Begin twisting switchbacks
  • N40 13.032 W105 18.399 — 2.0 miles : End switchbacks at bench and overlook
  • N40 13.216 W105 18.334 — 2.2 miles : Bitterbrush Trail - Antelope Trail junction
  • N40 13.596 W105 19.371 — 3.55 miles : Bitterbrush Trail - Nelson Loop junction
  • N40 13.271 W105 19.987 — 4.8 miles : Nelson Loop - Nighthawk Trail junction
  • N40 13.596 W105 19.371 — 5.85 miles : Nelson Loop - Bitterbrush Trail junction
  • N40 12.730 W105 17.365 — 9.4 miles : Bitterbrush Trailhead at Hall Ranch

Worth Noting

  • These are multi-use trails that see heavy use all year round. Honor yield protocols.

  • Do not enter or disturb historic remains.

Rules and Regulations

  • Dogs are not permitted on any trail within Hall Ranch.

  • Bikes are permitted on the Bitterbrush Trail and Nelson Loop Trail. They are not permitted on the Nighthawk Trail or Button Rock Trail.

  • Camping, hunting, fire arms and motorized vehicles are not permitted within Hall Ranch.

  • It is illegal to enter, move or remove historic remains found in Hall Ranch.

  • Horses are permitted on the Nighthawk Trail and Nelson Loop Trail at Hall Ranch. Equestrians are encouraged to remain on designated trails. Horses must be on a lead and may not be tied and left unattended. All trail users must yield to equestrians.

Directions to Trailhead

Hall Ranch in Lyons, Colorado:

From Boulder, take Highway 36 14 miles north to the Highway 66 junction in Lyons, CO. Turn left. Highway 66 will dead end at a "T" intersection on the west side of Lyons. Take a left on Highway 7 towards Allenspark. Hall Ranch is located 1.4 miles on the northeast (right) side of Highway 7.

Contact Information

Boulder County Parks & Open Space
5201 St. Vrain Road
Longmont, Colorado 80503
Phone: 303.678.6200
Fax: 303.678.6180

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