Wonderful resource for locals, but...

There are many informative reviews here, but I'd like to add some information that visitors or new residents may find useful.
First, as others have mentioned, Fresh Pond Reservation is a shared-use area which permits Cambridge-licensed dogs to be off leash in certain areas, none of which are fenced. Resident dogs are permitted off-leash on the main path, at Little Fresh Pond, and seasonally at Kingsley Field.
Also, visitors with dogs should be aware that they will be sharing the path with a mix of on-leash and off-leash dogs, runners, walkers, and bikers. If your dog can't be stopped from approaching (chases) runners, playing children, or cyclists, this is not the place for them to go off leash. Please also note that on- and off-leash dogs can be a dangerous mix, and leash-reactive dogs will find a trip here a hellish experience.
Swimming: Dogs are allowed to swim at Little Fresh Pond, which is approximately half-way around the 2.5 mile loop from the parking lot and Water Department building. The terraced entry isn't great but lots of dogs love it. Contrary to the introduction here on BringFido, there is only ONE pond for dogs to swim, as it is no longer allowed at Black's Nook, and was never allowed in the Reservoir itself.
Kingsley Field: This large multi-use field is next to the parking lot. Areas where dogs are permitted off-leash are different summer vs. winter, but the city keeps a clear map posted on a board as you approach. This area is not fenced, but is a popular spot for well-trained dogs to play fetch or with each other.
Getting there: As others have noted, parking is for Cambridge residents only, and only Cambridge-licensed dogs should be allowed off-leash. However, there are multiple access points onto the trail from Huron Ave and Concord Ave.
Lastly, though this space is a treasure for city residents, and I commend the city for their creativity, sharing can bring people into conflict. I have seen a few unpleasant interactions between visitors (leashed dog vs. unleashed dog, unleashed dog vs. runner), though they are vastly outnumbered by the positive ones.

Jun. 08, 2020