Established in the late 1600s, as part of Huntington South, the Deer Park area was sparsely habited, but its soil was rich and proved to be excellent for growing dahlias and fruits. The majority of ornamental trees and shrubs used to landscape Central Park were grown in Deer Park. In celebration of its agricultural industries, Deer Park was well known for its annual dahlia festivals.
Because its landscape was covered in scrub oak and pines, it was also known for its abundance of wildlife. One local resident is reported as describing the location of his home as "south, toward the Great South Bay . . . in the Deer Park."
The Long Island Rail Road arrived in Deer Park in 1842, establishing the first railroad station in the Town of Babylon. With the arrival of the railroad, a stagecoach route was established down Deer Park Avenue to Babylon. The ease of railroad access established the rural community as a popular destination for travelers heading to Ronkonkoma and the Great South Bay area. Rail transportation also facilitated many local industries, including Gulden's Pickle Works, established in 1902.
In 1872, it is reported that Deer Park consisted of one store, a one-room schoolhouse, and about a dozen homes. Today, Deer Park is the second most populous hamlet in the Town of Babylon.