UPDATED 12/9/2025: The closure of the southwestern quarter of the trail around Lake McIntosh has been delayed due to recent snowfall. The revised start date for the project is now December 22, 2025. Should further updates be necessary, they will be posted at longmontcolorado.gov/news. The closure is required for dam safety work and will last about 3 to 4 weeks.

The trail is located in northwest Longmont and connects the McIntosh Lake Nature Area (1929 Harvard St.) and Dawson Neighborhood Park (1757 Harvard St.) as well as circles Lake McIntosh. During the closure, trail users will not be able to complete the loop around the entire lake.

The Colorado Division of Water Resources, also known as the Office of the State Engineer,  has requested that the Lake McIntosh Reservoir Company repair the upstream side of the dam to maintain dam safety. The dam, and related work, are located in the southwest corner of the lake, indicated by the dotted line in the map below.

This work will require placing heavy equipment (an excavator) on top of the dam and removing and replacing “riprap,” the large rocks used to form the dam’s foundation.

If you have questions about the closure, please call the City of Longmont call center at 303-651-8416.

Media contact: Rogelio Mares
City of Longmont, Public Information Officer
PIO@longmontcolorado.gov or 720-899-0758