Lake Gardner Beach is the City of Amesbury's public swimming beach at the south end of Lake Gardner, an 80-acre impoundment of the Powwow (Powow) River a few blocks from downtown Amesbury. The lake was created in 1872 when the Salisbury Mills Corporation dammed the river for mill power, and the town bought the dam in 1952. The beach, lake and trails are city property, and the beach is run by the Department of Public Works, with the Lake Gardner Improvement Association (LGIA) handling trail work and much of the public information. The lake runs about 1.3 miles north toward the New Hampshire line, with homes along the western shore and wooded conservation land on the east.

The driveway is at 79 High Street, just north of where High Street crosses the Powwow below the dam. Parking is a small paved lot that the city rebuilt during a 2022 to 2023 renovation. Street parking near the entrance is not allowed, and LGIA notes that parking is enforced, so park only in marked spaces. If the lot is full, downtown Amesbury is a short walk away.

The beach is a sand strip looking up the lake from its southern tip, with grass and shade trees behind it. The roped swim area is shallow near shore and popular with families with small children, and the lake's maximum depth is about 17 feet out in the basin. As a slow-moving mill pond it warms up through the summer and has no real current inside the buoys. Swim within the buoy line. LGIA's beach page says there are no lifeguards and swimming is at your own risk, though older city and trail-guide pages mention summer lifeguards and swim lessons, so check with the Amesbury Recreation Office (978-388-8137) if guard coverage matters to you. A beach monitor is on site most summer days. Restrooms are open seasonally from May 15 to October 15 and cleaned daily.

There is no entry or parking fee, and LGIA describes the beach as open to Amesbury residents and visitors alike. The city does not post fixed daily hours online; questions about hours or closures go to the Recreation Office at 68 Elm Street. Groups of 10 or more need a city permit to use the beach, and groups of 25 or more must bring their own lifeguard. Dogs are not allowed on the beach from Memorial Day to Labor Day, smoking is banned, and fires and grills are prohibited at all times.

Water quality is the main thing to watch. The city tests for E. coli weekly from late May through Labor Day and posts results on its Water Quality Testing page, usually on Friday mornings. A count over 235 per 100 mL brings an advisory and over 1,000 closes the beach. Lake Gardner has failed tests in several recent summers, including June 2024 and August 2025, when it appeared on the state's closure list, so check the latest result after heavy rain. The dam and spillway sit just southwest of the beach; stay away from them. A 16-year-old visitor drowned here in June 2021.

Canoes, kayaks and other car-top boats can launch from the beach outside the swim area. There is no trailer ramp, jet skis are prohibited, and motorboats are limited to lakefront residents. From the beach a boardwalk and footbridge lead into the Powow River Conservation Area, where trails follow the undeveloped eastern shore. Paddlers can head north up the lake and into the Powwow River toward Tuxbury Pond.