Gillson Beach is the main public swimming beach in Gillson Park, the 60-acre lakefront park run by the Wilmette Park District on the Lake Michigan shore in Wilmette, Illinois. The park district calls it Gillson Swimming Beach or Main Beach, and it sits just north of Wilmette Harbor, with the white dome of the Baha'i House of Worship visible above the trees to the south. The village has had an official bathing beach at the foot of Lake Avenue since the early 1900s, and the park itself was once known as Washington Park.

Gillson Park has two vehicle entrances: the north gate at Lake Avenue and Michigan Avenue, and the south gate at Sheridan Road and Michigan Avenue. The park address is 800 Gillson Park Drive. Parking inside the park needs a separate parking pass through October 15. A daily parking pass is $17 for residents and $21 for non-residents on weekdays, and $21 and $26 on weekends. From October 16 no parking pass is required. Walkers and cyclists from the surrounding neighborhood can come in on foot without a parking pass.

The Main Beach is a long stretch of soft sand that runs out to open lake water, with the beach house and a food stand (The Fat Shallot) behind it. The bottom is sand and the water deepens gradually, but this is Lake Michigan: water temperatures swing hard with the wind, and an offshore breeze can drop it into the 50s even in July. Waves build quickly on a northeast wind, and currents run along the breakwalls and piers at both ends of the park. Lifeguards staff the beach in summer, and swimming is allowed only inside the guarded area.

Swimming isn't free. In 2026 a daily beach pass for the Main Beach is $11 for Wilmette residents and $17 for non-residents. Residents have to show ID. Daily passes are sold in person at the lakefront by credit card or Apple Pay only, with no cash and no refunds, and season passes are also sold. South Beach, opened to guarded swimming in 2024, is $5 or $10. Langdon Beach to the north is $11 or $17. Library cardholders in Wilmette, Skokie, Niles, Des Plaines, Morton Grove and Glenview can reserve a free Beach Bound pass through Explore More Illinois that admits up to six people to the Main Beach for a day (parking not included).

The swimming season runs Memorial Day to Labor Day, with beach hours of 10 am to 8 pm. Swimming after 8 pm is not allowed, and the park district says swimming is prohibited after Labor Day. Late in the season lifeguards drop to weekends only, so check the lakefront page before a late August visit. The park is open 6 am to 10:30 pm, the vehicle gates close at 9 pm (you can still drive out through Washington Avenue), and cars left after 10:30 pm are ticketed. The beach closes for swimming when bacteria levels test high, which happens most often after heavy rain, when stormwater and the North Shore Channel outlet at the harbor push runoff into the lake.

Beyond the swim beach, Gillson Park has a Sailing Beach with kayak, paddleboard and small sailboat rentals and a launch for people bringing their own boats, a fenced Dog Beach for permit holders, the Wallace Bowl outdoor theater, picnic groves and a pavilion, lighted tennis courts, a playground and the Lakeview Center. The lakefront office can be reached at (847) 256-9656.