The race starts and finishes at Battery Park and the Hudson River, just south of the Fire Boat House. Swimmers begin at the Battery then head north up the East River, counter-clockwise around Manhattan Island. They swim north into the Harlem River, through Spuyten Duyvil, and then south down the Hudson River to the Battery.
There are 4 check points: Hell's Gate where the East River meets the Harlem River, Spuyten Duyvil where the Harlem River meets the Hudson River, the 79th Street Boat Basin in the Hudson River, and the World Trade Center.
First Leg - The East River: Swimmers proceed up the East River under the Brooklyn Bridge, Manhattan Bridge and Williamsburg Bridge. Just beyond the second bridge in the East River (the Manhattan Bridge), the swimmers steer clear of the pier near the prison barge by adjusting the course towards the center of the river. On the left side of the river, at 23rd Street, swimmers watch for float planes taking off and landing. The planes dock at the marina near the "Gulf" sign.
The swimmers continue up the East River through the West Channel (Manhattan side), passing by Roosevelt Island. Swimmers are advised to keep to the Manhattan side of the Channel throughout the entire East River.
Second Leg - The Harlem River: Swimmers then head towards the leftmost stanchion on the footbridge at the entrance to the Harlem River at Hell's Gate. This is their first check point. Once they have entered the Harlem River, they will stay to their left. The swimmers take all bridges on their leftmost channel, allowing enough room for the Circle Line and other boat traffic to pass.
Final Leg -The Hudson River: At Spuyten Duyvil, where the Harlem River joins the Hudson River, the swimmers pass their second check point. They head down the Hudson River towards the George Washington Bridge, staying about one-third of the way from the Manhattan side. After coming under the GW Bridge, the swimmers must stay as far enough out from shore so that they are not swept into the sewage disposal plant, which protrudes out about a quarter of a Mile. This plant spans 10 blocks, from 145th to 135th Street.
The swimmers continue down the Hudson River on the Manhattan side. Their third check point is opposite the 79th Street Boat Basin. The swimmers are advised to stay to the Manhattan side of the river. As they come down the Hudson, the swimmers must be careful of boats coming out of the piers, especially between 50th and 23rd streets. Swimmers are not allowed to swim closer than 20 yards to the end of any pier.
As they near the finish, the swimmers see the Twin Towers of the World Trade Center. Their fourth check point is opposite the World Trade Center. The swimmers then swim along the concrete bulkheads to the Fire Boat House Pier. As they come around it, they will swim back to the cheering crowds at Gangway 6, Battery Park.