More than 800 swimmers will dive into Long Island Sound on Saturday for one of Westchester's biggest annual fundraisers, with millions of dollars on the line for cancer research and local patient care.

The 34th annual Swim Across America – Long Island Sound begins at Larchmont Yacht Club and features 2K, 5K and 10K open-water swims. The signature 10K route starts in Glen Cove on Long Island and finishes in Larchmont. A half-mile pool swim at Larchmont Shore Club offers a shorter option for participants.

Organizers hope to raise $2.15 million this year. Since the event began in 1992, it has generated more than $32 million for cancer research and treatment programs.

Part of that money stays close to home. One of the beneficiaries is Cancer Support Team in Mamaroneck, which provides free nursing, counseling and support services to nearly 700 cancer patients and families each year across southern Westchester, including Bronxville, Scarsdale and Eastchester.

Funds also support research at Memorial Sloan Kettering, Columbia University Medical Center and Weill Cornell Medicine. Swim Across America says donations from the Long Island Sound event helped fund a Memorial Sloan Kettering clinical trial that reported complete remission in a group of colorectal cancer patients.

Although online registration has closed, swimmers can still register in person beginning at 6 a.m. Saturday at Larchmont Yacht Club. Volunteers are also still needed to help on land and on the water.

If you're not swimming, the event is worth stopping by to cheer on participants as they tackle one of the region's most challenging endurance events. Two additional Swim Across America pool events are also scheduled nearby: July 30 at Scarsdale Golf Club and Aug. 1 at Lake Isle Country Club in Eastchester.

Donations to support the cause remain open through the Swim Across America Long Island Sound campaign.