Amended fire restrictions: Stage 1 fire restrictions in western Boulder County. Fire restrictions rescinded in eastern Boulder County.

Carolyn Holmberg Preserve at Rock Creek Farm
Carolyn Holmberg Preserve at Rock Creek Farm

Carolyn Holmberg Preserve at Rock Creek Farm

Cradleboard Trail detour begins Oct. 15. Learn More

An oasis of calm in the midst of urban life, Carolyn Holmberg Preserve offers a tranquil setting for both humans and wildlife. Look for waterfowl and raptors at Stearns Lake and in surrounding fields. With luck, you may see bald eagles that regularly hunt here.

Trails

  • Cradleboard Trail
    1.3 miles – Easy
    Hiking Allowed Dogs Allowed Bikes Allowed E-bikes Allowed Horses Allowed
  • Lac Amora Link
    0.3 miles – Easy
    Hiking Allowed Dogs Allowed Bikes Allowed E-bikes Allowed Horses Allowed
  • Mary Miller Trail
    1.5 miles – Easy
    Hiking Allowed Dogs Allowed Bikes Allowed E-bikes Allowed Horses Allowed
  • Ruth Roberts Connector Trail
    0.9 miles – Easy
    Hiking Allowed Dogs Allowed Bikes Allowed E-bikes Allowed Horses Allowed

Rules & Regulations

Day Use Only
Bikes On Designated Trails Only
Pets On Leash
No Camping
No Swimming
No Boating

All Parks & Open Space Regulations

Trailhead Amenities

25 car parking spots
2 ADA van accessible parking spot
Restroom near main trailhead
25 person group shelter located near main trailhead Reservation Info
Live view of the Stearns Lake parking lot at Carolyn Holmberg Preserve
Live view of the Stearns Lake parking lot

Keep In Mind

  • Stearns Lake trailhead can be accessed from Dillon Rd and 104th St. There is no access from 287 through Rock Creek Farm.
  • The Carolyn Holmberg Preserve connects with the Rock Creek Trail.
  • Regional trails and regional trail connectors are open to commuters 24 hours per day. Trailheads close at sunset and parking is not allowed between sunset and sunrise.

Beginning Tuesday, Oct. 15, a detour will be in place along a section of the Cradleboard Trail to protect territorial bald eagles.

The birds lost their nest when lightning struck a tree in August. Their territory has few suitable nesting trees, including one along the trail near their old nest.

The closure will be in place again this fall until the eagles’ nesting status is confirmed. If they nest elsewhere, Colorado Parks and Wildlife will be consulted about whether to reopen the trail.

Boulder County adheres to all state and federal protection guidelines for raptors, and may impose stricter protections as necessary.

Map showing the trail detour at Carolyn Holmberg Preserve

Trailhead improvements were completed on Oct. 15. The project included an expansion of the parking lot, surface grading, two new culverts for improved drainage, and a concrete sidewalk from the accessible parking to the restroom and the kiosk. Parking spaces increased to 25 regular parking spots and two ADA van accessible parking spots. There is no trailer parking in the new lot.

Construction design plan showing the improvements to the trailhead.

Stearns Lake is a great place to fish.

Fishing at Stearns Lake

  • Bluegill (limit 20), Channel Catfish (limit 10), Tiger Muskie (limit 1 of 36” or larger), Largemouth Bass (limit 5 over 15″).
  • Artificial and live bait permitted.
  • Boats and float tubes are not permitted.
  • The northwest shoreline is permanently closed.
  • Summer Catfish Nights are held annually at Stearns Lake. Check the Hike & Events Calendar for details.
  • Learn more about Fishing on Open Space

Visitation by Day of Week

Bar chart showing Saturday and Sunday and the busiest days

Visitation by Hour

Bar chart showing 11am is the busiest hour of the day on Saturday and Sunday and noon Monday through Friday

Visitation by Month

Line graph showing April through September are the busiest months of the year

Visitation by Location

Pie chart showing visitation by location. The main trailhead had the most visits (44%).

In the shadow of the Rocky Mountains, the Great Plains is dry, windy, and expansive. Receiving only small amounts of precipitation, the 1,136 acres of Carolyn Holmberg Preserve is dominated by grasses. The scarcity of water prevents larger shrubs and trees from growing, except along waterways. However, the soils are rich, allowing a wealth of other plants to thrive. These plants, in turn, support a variety of animal species.

Mammals

  • Black-tailed prairie dog
  • Coyote
  • Desert cottontail
  • Muskrat
  • Raccoon
  • Red fox
  • Striped skunk
  • Western harvest mouse

Birds

  • American avocet
  • American kestrel
  • American widgeon
  • American white pelican
  • Bald eagle
  • Barn swallow
  • Burrowing owl
  • Canada goose
  • Common goldeneye
  • Common merganser
  • Common nighthawk
  • Great blue heron
  • Great horned owl
  • Killdeer
  • Mallard
  • Mourning dove
  • Northern oriole
  • Northern shoveler
  • Red-tailed hawk
  • Red-winged blackbird
  • Ring-necked duck
  • Snowy egret
  • Song sparrow
  • Swainson’s hawk
  • Western grebe
  • Western kingbird
  • Western meadowlark

Fish

  • Bluegill
  • Channel catfish
  • Tiger muskie

Plants & Trees

  • American vetch (Vicia americana)
  • Cattail (Typha latifolia)
  • Curlycup gumweed (Grindelia squarrosa)
  • Scarlet globemallow (Sphaeralcea coccinea)
  • Peachleaf willow
  • Plains cottonwood

When gold was discovered near Gold Hill, miners streamed in to seek their fortune. Most people left broke and disillusioned. Some, however, started a new life farming.

Two of those pioneers were Mary and Lafayette Miller. They came west in 1864 and purchased an 80-acre parcel of land on Rock Creek that included a hotel and tavern and a stage station. They also ran a cattle ranch and meat market in the area.

During the past century, this open space property has been used to raise crops and livestock, and was also home to a dairy farm. Boulder County purchased a portion of Rock Creek Farm in 1980 for agricultural preservation and as a buffer between the growing communities in southeastern Boulder County.

The property is dedicated to Carolyn Holmberg, a former Parks and Open Space director who died in 1998.

Renting the Goodhue Farmhouse

The Goodhue Farmhouse, rehabilitated in 2004, was originally built nearly 100 years ago. It is closed to the public, but is available to rent to municipalities, environmental and historical nonprofits, and other nonprofits that partner with Boulder County government.

Learn more about renting the Goodhue Farmhouse.

Goodhue Farmhouse

Contact Us

Parks & Open Space

8 a.m. to 4:30 p.m.
Monday-Friday

Office Location

5201 St. Vrain Road
Longmont, CO 80503
Map and Directions
Office Hours: 8 a.m. to 4:30 p.m.
Monday-Thursday
Friday by phone, email, or appointment only.

Parks are open sunrise to sunset