Willow Beach is where the Colorado River comes out of Black Canyon on the Arizona side, 14 miles below Hoover Dam by water, and it is the only developed river access in that whole stretch of Lake Mead National Recreation Area. The day-use beach is a strip of sand and gravel on a calm eddy just off the marina, with covered picnic tables and grills behind it and a fishing pier alongside. The water is startling: Hoover Dam releases from deep in Lake Mead, so the river here runs 53 to 54 degrees year round and glass clear, green over the gravel bars and blue-black in the channel. On a 110-degree July afternoon the shock of it is the point. Swimmers stay close to the beach; the current picks up quickly once you are out past the eddy. There are no lifeguards.

Everything on shore is run by the park concessioner as Willow Beach Harbor. The marina rents kayaks, canoes, paddleboards and motorboats, sells fuel and has a store and the Black Canyon Grill. The launch ramp reaches the river at any lake level, which has made it busy as Lake Mead's other ramps have gone dry. Upstream, the river is closed to motors on Sundays and Mondays, and those are the days to paddle: Emerald Cave, the little grotto that glows green when the sun hits the water, is two miles up, and Arizona Hot Springs is a longer pull to the head of the canyon.

The campground on the bench above the marina has 28 full-hookup RV sites at about $80 a night and nine walk-in tent sites at about $45, with 24-hour showers and laundry, checked in at the store between 8 and 4. Two leashed pets per site. There is no cell service. On top of the camping or day-use, the park entrance fee is $25 per vehicle for seven days ($20 motorcycle, $15 walk-in, $45 annual), and motorized boats need a $16 lake use pass; non-motorized boats are exempt. Everything is cashless.

Next to the marina is the Willow Beach National Fish Hatchery, a U.S. Fish and Wildlife Service station opened in 1959 that raises the rainbow trout stocked into the river here and, more recently, endangered razorback suckers and bonytail chub for the lower Colorado. The tailwater trout fishing off the pier and from the beach is some of the best in Arizona. Archaeologists have also found that this bend was a trading site for Native peoples from about 500 to 1200 CE, with goods from as far as the Pacific coast.

Willow Beach is at the end of a four-mile paved spur off US 93, about 30 minutes from Boulder City and 45 from Las Vegas. The address is 25804 N Willow Beach Road; the harbor's phone is 855-918-5253.