Section of Twomile Mesa Trail closed for construction

A section of the Twomile Mesa Trail has been closed indefinitely for construction and future operations. For safety of trails users and the safety of construction crews, please follow the trail detour extending north/south along West Jemez Road (NM 501). The trail will be rerouted for future sustained use. Twomile Mesa Trail runs behind the Emergency Operations Support Center (EOSC) and south along West Jemez Road (N.M. 501). The closed section is on Department of Energy (DOE) land. For the safety of trail users and construction crews, follow the temporary trail detour. Trail users will exit the Twomile Mesa Trail and use the east shoulder of N.M. 501 for half a mile and then re-enter the trail. Do not cross the trail closure signage. Please note: the Twomile Mesa Trail is open to Los Alamos National Laboratory badge holders only.

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Interactive map for Los Alamos Area Trails

Lab trails reopened: As a reminder, trails on Laboratory property have reopened concurrent with the recent downgrade to Stage II fire restrictions. Existing trailhead closure signage and barriers will be removed soon.

If a trail needs maintenance, notify the Lab's trails team. Don't forget that trail users aren't permitted to create new trails or modify existing trails on Laboratory property. If you see a trail that needs maintenance, please email


Maintaining our Trails

Recreational trails use at Los Alamos National Laboratory has always been highly valued as one of the benefits of working and living in Los Alamos County. Laboratory trails are uniquely located on Department of Energy (DOE) land. Continued public access is conditioned upon treating the land and its resources with care and consideration. Please continue to notify the Trails Management program of any concerns about the trails.

Trail users should not attempt to clear downed trees or other major obstructions on any Laboratory trails, as the trails are on DOE land and some trails present unique hazards, which are posted at each trailhead kiosk.

Input on trails from trail users is paramount to successful maintenance and care of the trails. To report a trail condition or concern or to contact the Trails Management Program, email

Some Laboratory trails are open to the public whereas others are only open to Laboratory badge holders. Some trails allow dogs, horses, and bicycles while these are prohibited on other trails. It is your responsibility to understand the rules of a particular trail.

Trails are open from dawn to dusk, however trails and trail segments shown in red on trail maps are closed to all entry.

Hike open trails at your own risk; carry water, and beware of weather conditions, hazards, and wildlife.

Please leave no trace and pack out your trash.

Laboratory trails in the White Rock area (TAs 70/71) are actively patrolled by Bandelier National Monument rangers through an agreement between the National Park Service and the Department of Energy.

Other Lab trails may be monitored by the Laboratory's Protective Force.

You are required to acknowledge and comply with law enforcement requests and directions.

Report illegal or suspicious activity to: 505-667-2400

To send general inquiries or feedback:

Karla Sartor
LANL Trails Management Program Lead
(505) 667-8719

The following activities and items are strictly prohibited on Laboratory trails.

alcohol consumptionfires
collecting natural or cultural materialsgeo caching
digging or ground disturbance

hunting or trapping

disorderly behaviormemorialization
disturbing archaeological resourcesmotorized vehicles (unless performing official LANL business)
dumping or disposal of trashsmoking
wood gathering 

Trails Working Group

The LANL Trails Working Group inventories, maps, and prepares historical reports on the many trails used at LANL. Some of these trails are ancient pueblo footpaths that continue to be used for recreational hiking today. Some serve as quiet and non-motorized alternatives between the Townsite and LANL or between technical areas.

The Trails Working Group, established in December 2003, includes representatives from local citizen hiking groups, Los Alamos County, Forest Service, Park Service, Los Alamos National Laboratory and the NNSA Los Alamos Site Office. Trail Working Group meeting notes are available upon request. Please contact for more information.

The Trails Working Group carries out the Trails Management Program, which was a requirement stipulated in an NNSA environmental assessment and Finding of No Significant Impact (FONSI) (PDF) completed in 2003. The program addresses various issues related to hiking on Laboratory property. Through this program, an active needs assessment was completed on how to manage foot traffic, control looting and vandalism, protect the scientific value of sites near trails, and provide the proper respect for sites that are sacred to local pueblos.