The large estate, covering more than 1,300 acres (530 ha), is located near the junction of U.S. Route 302 and Interstate 93, and includes some twenty buildings.

The estate was assembled by John Jacob Glessner (whose Chicago residence is a National Historic Landmark designed by H. H. Richardson) in the 1880s, and is one of the largest and best-preserved surviving private estates in the state.

Glessner created The Rocks as a private conservation initiative, to prevent destructive farming methods from destroying the land.

[2] The property is now owned by the Society for the Protection of New Hampshire Forests and is open to the public.

It is managed by that organization according to principles articulated by Glessner, preserving an important aspect of the property.