MA
Nowhere in the reservation, and this one is year-round — Walden is named on DCR's blanket 'not allowed' list, not on the seasonal beach list (DCR's separate seasonal rule bans dogs from coastal beaches and inland swimming areas 1 May–15 Sept, but that is not what excludes Walden; Walden is excluded all year). DCR also bars dogs from "DCR parking areas" system-wide, so you cannot walk a dog in the Walden car park while someone else swims. ADA service animals are a legal exception, though the DCR page does not spell it out. Dog-legal walking sits immediately next door on Town of Concord conservation land — Concord's own 'Dogs on Conservation Land' page notes "More than 70 percent of Town conservation lands remain open to off leash dog walking" (leash requirements vary by parcel; check the Town's map first).
Managed by Massachusetts Department of Conservation and Recreation (DCR). Official pet policy. Checked against that page in August 2026.
We publish this because finding out at the trailhead is worse than finding out here. Rules change — check before a long drive.