New England National Scenic Trail Designation Act - Amends the National Trails System Act to designate the New England National Scenic Trail as a National Scenic Trail.
Directs the Secretary of the Interior to use the Trail Management Blueprint as the framework for management and administration of the Trail.
Authorizes the Secretary to enter into cooperative agreements with Massachusetts (and its political subdivisions), Connecticut, (and its political subdivisions), the Appalachian Mountain Club, the Connecticut Forest and Park Association, and other regional, local, and private organizations deemed necessary and desirable to accomplish cooperative trail administrative, management, and protection objectives consistent with the Blueprint.
Encourages the Secretary to work with New Hampshire and appropriate local and private organizations to include that part of the Metacomet-Monadock Trail in New Hampshire (which lies between Royalston, Massachusetts and Jaffrey, New Hampshire) as a component of the Trail.