Tucked away in the northwest corner of Lewisboro is the delightful 50-acre Mount Holly Preserve. Almost adjacent are the Marian Yarrow Preserve, Mildred Grierson Preserve, and the Mount Holly Sanctuary, together totaling 230 acres. The three preserves on the east side of Mt. Holly Road – Marian Yarrow, Mildred Grierson, and Mt. Holly Preserve – are called the Indian Brook Assemblage and are owned and managed by the Lewisboro Land Trust. The Mt. Holly Sanctuary, on the west side, is owned and run by The Nature Conservancy.

The Mount Holly Preserve has two entrances, one on Mount Holly Road that is especially convenient for neighbors, and a second entrance on Mount Holly Road East which allows for parking. Immediately upon entering the preserve at either entrance, one will quickly appreciate its rugged, well-maintained trails. This is done through the tireless efforts of many volunteers and gracious helpers. An Eagle Scout project, completed in 2020 by Andrew Lucassen, expanded the first entrance and added a seating area within the preserve.

The preserve itself is over 50 acres and contains nearly two miles of well-marked and easy-to- navigate trails. With modest elevation gains throughout, the preserve has four different trails: yellow, green, orange, and its most used, red trail. Maps are conveniently displayed at kiosks at either entrance. Highlights include meadow wildflowers, the Indian Brook which flows along the eastern boundary to the Cross River Reservoir, and large cliff outcroppings made of 6-million-year-old Fordham gneiss. The eastern portion of the red trail terminates alongside a lush wetlands area, an important ecological feature that promotes water quality and flood control, while providing a unique habitat for many endemic species. A popular area known as “The Clearing” provides an internal sanctuary within the preserve, where one can pause, reflect, and absorb one’s surroundings.

The preserve itself was donated to The Nature Conservancy in 1975 by Frances Duncombe, the distinguished author of the book, “Katonah: A History of a New York Village and Its People.” In 1979, Leslie and Susan Simon donated an easement on Mount Holly Road East to allow parking access to the preserve from that road. The Nature Conservancy owned and managed the property, along with the Marian Yarrow and Mildred Grierson preserves, until 2020, when it was acquired by the Lewisboro Land Trust. In the short time that LLT has been managing the preserve, trails have been widened, invasive Japanese barberry curtailed, and new trail blazes installed. It has also become a popular place for educational and outdoor programming, including the Town of Lewisboro’s First Day hikes, monthly mediation programs, teen adventure hikes, Arbor Day tree planting celebrations, the Hudson River Valley Ramble, and most recently, a fall mushroom identification hunt.

The preserve is open (and free) from dawn to dusk, horses are welcomed, and hunting is not permitted. Parking is available on Mount Holly Road East. Guests are asked to conform to Leave No Trace principles in an effort to continue making the preserve a pleasant and natural place for many to enjoy for years to come.