Brentwood has a lot of nooks and crannies for your dog.  The main dog park on Barrington is large, and often crowded with dog walkers during the week during peak hours (11am - 2pm).  I often can be found there a couple of days a week proofing training in front of the dog park, using the area as a distraction.  Rarely do I use this park for socialization as it is crowded, and crowded parks often have aggression outbreaks I don't want a dog I am socializing to see.

Another location in Brentwood is Hanley Park.  This is NOT a dog park, and is posted with "Dogs Must Be On Leash" signs.  However, I have found this place to be a good traininig location, and use long ropes to train recall and stay commands.  I have found if your animal is under control it is rare anyone will say anything to you about the leash law.