East Mountain is the southerly extension of the basalt ridges that make up Mt. Tom in Holyoke. The section of ridge that is called East Mountain extends from Route 141 in Holyoke and Easthampton south through West Springfield and Westfield to the Massachusetts Turnpike. This circumneutral ridge of basalt continues south well into Connecticut.

Swamp Lousewort (Pedicularis lanceolata), Endangered

Four properties in Holyoke and one in Southampton make up DFW's East Mountain and Southampton Wildlife Management Areas. North of Route 141, DFW owns a small parcel on the eastern slope of Mt. Tom itself (not shown on the map). A significant portion of East Mountain is owned by the Holyoke and West Springfield Water Departments, and other properties on East Mountain are protected by the City of Easthampton, the Connecticut River Watershed Council, and the Holyoke Conservation Commission . Together with the Mt. Tom State Reservation and lands protected by the Silvio O. Conte National Wildlife Refuge and The Trustees of Reservation on the Mt. Tom ridge, much of the exceptional habitat on Mt. Tom and East Mountain is protected from destruction through development.

More than twenty state-protected rare plants and animals have been documented from East Mountain, including Marbled Salamander (Threatened), Wood Turtle (Special Concern), Swamp Lousewort (Endangered), and Green Rock-cress (Threatened).

The Metacomet-Monadnock Trail runs along the ridgelines of East Mountain and Mt. Tom, including through DFW land. Hiking this trail will give you spectacular views west towards the Berkshire foothills and, more importantly, a sense of the exceptional richness of natural communities and unusual bedrock making up these basalt ridges.