Deer Park is a hamlet and census-designated place in Suffolk County, New York, United States. Located on Long Island, the area is part of the Town of Babylon. As of the 2010 census, the population of Deer Park was 27,745.

Deer Park is home to the Long Island Rail Road station, Deer Park. The nearby Robert Moses Causeway provides a direct route to the Fire Island beaches. The Long Island Expressway and the Northern State Parkway are also nearby.

The area is served by the Deer Park Union Free School District, which consists of five elementary schools, two middle schools, and one high school. The high school, John H. Glenn High School, has a wide variety of extracurricular activities and sports teams.

The area is home to several parks, including Sumpwams Creek Park, Deer Park Arboretum, and Deer Park Town Park. These parks offer a variety of activities, such as hiking, basketball, volleyball, and baseball.

There are several shopping centers in the area, including the Deer Park Town Center and the Deer Park Shopping Center. The area also has a variety of restaurants, ranging from fast food to fine dining.