The Ashley Reservoir is the secondary drinking supply for the city of Holyoke. The reservoir, consisting of Wright Pond and Ashley Pond, became fully operational in 1897. Ashley Reservoir is connected to a smaller reservoir McLean Reservoir, named after Holyoke Water Works Commissioner Hugh McLean. The reservoir has a surrounding gravel road.

The reservoir is home to bears, deer, geese, ducks, beavers, and many other animal species. Maple, oak, and red and white pine line the uplands, with red osier, alder, buttonbush, and other wetlands shrubs closer to the water. Sunfish and milfoil can be seen underwater.

Most areas around the reservoir are publicly accessible only by foot, with limited parking available at some of the surrounding gates.

There is a 4.5-mile loop trail at Ashley Reservoir. This is a very popular area for birding, hiking, and mountain biking.

The AllTrails website has a description and map of a hike at the Ashley Reservoir.