The Land Stewardship Committee of the Acton Conservation Commission has a website with great trail maps and descriptions of most of the Conservation Land in Acton.
Acton Conservation Land
Part of the description of Stoneymeade from that website:
“Stoneymeade Conservation Land was donated to the town in 1989. Located off Pope Road in East Acton, this conservation area borders conservation land in the town of Concord. Stoneymeade’s 44.5 acres preserves one of the largest remaining open fields in Acton, but it is also a mix of fields, small streams, and bordering woods. The distant vistas seen from the main field encompass a small pond surrounded by marshy growth, more fields beyond, a horse farm with corrals, and forestland on the far edge. Much of what can be seen here is in Concord, but the boundary between the two towns is seamless, enabling both towns to enjoy this tranquil open area. On the Acton side, the field is kept open by mowing late each fall to prevent forest succession from occurring.
Stoneymeade’s main entrance is from the far side of Stoneymeade Way, off Pope Road, where a prominent sign marks the beginning of an access trail. A short walk along this pleasant, tree-shaded path brings one to the large open field that makes up most of the Stoneymeade Conservation Land. A large, stately oak tree surrounded by ledge stands in the center of the field. The other access is from the town of Concord. The distance from the entrance on Stoneymeade Way to the boundary with Concord is only 0.4 mile.”
This trail is part of the Bay Circuit Trail. So, for a longer hike you can continue into Concord's Annursnac Conservation Land (see trail map). The woods at the edges of the field mark the Acton/Concord town line. There you can see the remains of a WWII era bunker on the left. Further in you'll eventually get to the start of the Relay Challenge Series.