Join the Semper Fi Fund Team for the 2018 TCS New York City Marathon! The TCS New York City Marathon course is a 26.2-mile block party through the world’s most diverse city, and it’s a model for big-city marathons around the world. The New York City Marathon has grown from a Central Park race with 55 finishers to the world’s biggest and most popular marathon, with nearly 50,000 finishers in 2017.