Location: Grand Army Plaza and Flatbush. There are many places to enter Prospect Park, please keep your dog on a leash until you are in a designated off leash area and only do so at designated times. Prospect Park Southwest, Prospect Park West, Parkside Avenue, Ocean Avenue, and Grand Army Plaza. Parking may be tough, but not impossible. Bring your own poop bags. trash cans are provided. (Thank you Jennifer Brauer)