One of the objectives of the redevelopment of Devens is the protection of environmentally sensitive areas including wetlands and floodplains, and forming an interconnected network of natural areas. Open Space accounts for approximately 1,700 acres at Devens and is part of a larger regional matrix of protected land extending along the Nashua River Valley.
This area supports wildlife habitat as well as numerous rare plant species. Most notably and frequently observed is the Blanding's Turtle. The Nashua River Valley is also designated under the North American Waterfowl Management Plan as a significant habitat for migratory birds.
Mirror Lake is an example of a kettle hole, a deep pond that formed when the last glacier to cover New England slowly melted away. Visitors are welcome to swim, picnic, boat, canoe or fish during regular season. A boat ramp is located at the end of Mirror Lake Road and electric trolling engines are allowed. Parking is available in designated areas.
Little Mirror Lake is located to the east of Mirror Lake and is also protected by preservation restrictions. Active and interesting wildlife exists throughout the area.
Black Spruce Bog is an ecological formation composed of a vegetated floating mat surrounded by a moat. This environmental feature is very uncommon and can be found to the southeast of Mirror Lake.
The Eskers are steeply sloped land formations created as stream beds which ran within ancient glaciers. This long, narrow ridge densely vegetated with trees and smaller vegetation helps to prevent erosion.
Robbins Pond is a shallow pond known more for its plant life. The area includes a walking trail and provides a great spot for picnics.