The Great South Bay Run starts and finishes at Bay Shore Marina Park in Bay Shore, New York, with the Great South Bay and Fire Island visible from the finish. This annual road-running series, sponsored by Northwell Health, offers three USATF-certified courses: a half marathon, a 10K, and a 5K Family Fun Run.
The routes guide runners through Bay Shore’s historic downtown before proceeding along residential streets near Brightwaters Lakes, Cascades, and Canals. The field typically numbers between 500 and 1,000 participants, giving it the feel of a local Long Island race day rather than a large city marathon. The program accommodates half-marathoners, 10K runners, families, and newer runners.