Pets on a leash no longer than 6 feet are allowed in the Chattahoochee River National Recreation Area. The area is a series of parklands along a 48-mile stretch of the Chattahoochee River between Atlanta and Lake Sidney Lanier. Three of the sites are in Sandy Springs, GA. Pets are allowed on park trails, but must be leashed at all times, including while in the water.
More information on the Chattahoochee River National Recreation Area pet policy