390-acre Skinner State Park on top of Mount Holyoke offers breathtaking views of the Connecticut River Valley. The summit is accessible by road from April through November, and by hiking trails year-round. The Summit House, a popular mountaintop hotel in the 1800's, is open for tours and programs on weekends and holidays from Memorial Day through Columbus Day, offering historical displays and special events. The park is named after Joseph Allen Skinner, a wealthy industrialist who donated the hotel and land to the state in 1940.

There are 20 picnic sites on the grounds, many with fine views and charcoal grills. Restrooms are available. Hawk watching is popular in spring and fall. Hang-gliding is allowed by special permit. Paths from the Summit House connect with marked trails that traverse the Holyoke Range. Fall foliage viewing is poular in the park, and the masses of flowering mountain laurel present a lovely spectacle in June. The park's Friends group offers hikes throughout the year and hosts a sunset concert series inside the Summit House each summer, and an annual Mountainfest in the fall. Wheelchair access at the summit is difficult due to the steep terrain and the historic nature of the Summit House. Please call the park for more details.

The mountain formed some 200 million years ago when lava flowed from the valley floor, cooled and was upended. More recently, glaciers left their signature, scouring the mountain's jagged edges smooth in some places, exposing bedrock or leaving till, sand, clay or muck in others.