Overall Run in Virginia’s Shenandoah National Park is best known for having the tallest waterfall in the park, at 93 feet. While impressive and beautiful when the stream runs high in the spring, during summer months the falls are but a mere whisper of water. Still, the flow is enough to fill a series of three interconnected swimming holes two miles downstream—one pool can get more than seven feet deep. The creek runs over a smooth, sloping rock wall that works as a fantastic water slide.

This 78-foot-tall waterfall—the largest in Maryland—isn’t a simple wall of water coming off a cliff edge. Rather, the water majestically cascades down through a series of ledges to a catch pool at the bottom—where you can wade into the cool mountain water. Although the park discourages climbing on the waterfall, many clamber up anyway, sitting beneath the torrents of water to get a massage on their backs and shoulders.

Want a place to swim where you can really dive in deep? Head to the Beaver Dam Swimming Club. This 40-foot-deep freshwater-filled quarry just north of Baltimore features several floating platforms, a rolling log to challenge your balance, a diving board, and a thrilling rope swing atop a high platform. Though the queue for the swing can be long on weekends, it’s worth the wait.

In a town called Poolesville, there has to be a swimming hole, right? There is. On River Road in Maryland, a hundred feet west of its intersection with Seneca Road, Seneca Creek passes under a bridge where a natural, shaded hollow makes for a delightful and secluded spot to take a dip. Though shallow, the stream includes large, flat rocks that let you sit or lie in the cool, clear flowing water. If you want to float in the creek, bring some rope and tie your “floatie” to a tree so you don’t dri

When it comes to options for cooling off, this Maryland park has the rest beat by miles: Swimming is allowed along much of the 32 miles of Patapsco River that runs through the park. The 16,043-acre park is divided into eight sections, each with a variety of trails along the river—including paved pathways, mountain-biking trails, and multiuse footpaths. Anyplace you don’t see a dam or whitewater rapids—where there are prohibitions against swimming—feel free to saunter into the water.