Sand Hollow State Park, about 13 miles east of St. George, combines a reservoir with a large area of red sandstone dunes and ATV trails. The reservoir is the main draw in summer — the water is warm, the swimming is safe, and the red rock backdrop is dramatic. Boat rentals, jet skis, and paddleboard rentals are available at the marina.
The dunes area on the eastern side of the park is open to off-road vehicles and draws serious ATV and dirt bike riders from across the region. There are also good hiking trails in the sandstone if you prefer to stay on foot. The park is year-round and considerably less crowded than Zion, which makes it a good option when you want to swim or be outdoors without navigating Zion's shuttle system.