Changes are underway at a popular mountain on Colorado’s Front Range.

The city of Boulder recently announced starting what’s been described as “a multi-year trail and ecological restoration effort” on Mount Sanitas.

The city has reported more than 300,000 people a year hitting the summit trails close to town — many of them tourists and local runners drawn to the steep challenge and rewarding views. The trail from Mapleton Drive climbs 1,300 feet in 1.3 miles.

Mount Sanitas “provides a unique outdoor experience,” noted a city news release. “However, the rugged, erosion-prone trails that make the area so popular also require extensive, long-term trail maintenance.”

Officials with Boulder Open Space and Mountain Parks have long worried about visitors roaming off trail and trampling plants, simultaneously blazing vertical paths that advance damaging erosion. Closing and restoring those “social trails” will be a priority this summer. Other top priorities: “repairs and improvements” along the main Mount Sanitas Trail and East Ridge Trail and “extensive maintenance” around the summit.

A $1.1 million grant from the Land and Water Conservation Fund is supporting work in the months ahead — continuing recent years that have seen timber checks, retaining walls and stone steps built along trails.

The Boulder Open Space Conservancy has also raised funds for the work. In the news release, the organization’s executive director, Alyson Duffey, called Mount Sanitas “iconic” and responsible for “special outdoor experiences for generations of community members and visitors from near and far.”

That’s been the case since the days of the Boulder-Colorado Sanitarium, built in 1896. Mount Sanitas got its name from that health and wellness retreat.

Boulder Open Space and Mountain Parks considers Mount Sanitas Trail one of its adopted “legacy trails” — long predating the department’s formation and modern trail construction standards.

“Legacy trails” are “steep and rugged and located in a higher terrain that provide a remarkable, enjoyable experience,” city spokesperson Phillip Yates said in a previous interview. “With that does come some higher maintenance costs. But we recognize the experience is just so unique, and we work to have those trails for our community.”

This summer marks one phase of work on Mount Sanitas. Next phases call for new trail connections to neighborhoods northeast of Sanitas and to historic rock quarries on the mountain. The city also seeks to improve and restore areas around bouldering sites.

No closures are expected during this summer’s work, “but visitors may experience intermittent delays,” according to the city.