Gate 30 at Quabbin Reservoir in New Salem, Massachusetts is an easy 0.8 mile out-and-back hike along a service road that runs through the norther woods of the reservoir.
The trail is most popular for the stone bridge that passes over a creek that feeds into Quabbin, which can be found just a hundred feet from the trailhead. During the Summer you can often find Fire Pink flowers lining the banks of the creek.
The trail itself continues much further than 0.4 miles one-way, but there's not much to see as the service road does not meet the water.
No dogs allowed on this trail or at Quabbin.