About 1725, the Town of Huntington decided to promote settlement in the Eastern Plains area, including a community called North Dix Hills. A tract of land almost 2 square miles was surveyed, and farmers moved in to take advantage of the flat land and fertile soil.

A general store was founded between 1850 and 1870 by one of the earliest residents, Jacob Soper, in his house at 462 Elwood Rd. It survives as a private residence. One of Soper's sons, Henry Edgar Soper, who lived next door to his father and helped out in the store, decided the community should have its own post office. In 1873, he got the job as first postmaster, working out of the general store. It was at that point that North Dix Hills became Elwood. No one knows how the name Elwood was chosen. The initial 2-square-mile settlement eventually grew to 5 1/2 square miles with the current Elwood school district boundaries. Major growth did not come to Elwood until well after World War II. In 1950, the census put the population at 300, and five years later the hamlet still had many dairy farms. Housing began to boom in the late '50s. The current population is almost 11,000.

Edward Lange, a renowned Long Island artist, resided in the Elwood area. Born in Germany in 1846, Lange in 1872 took title to three tracts of land near the Commack border and started to farm. He painted scenes of homes, towns and farms near his homestead in his spare time. In 1880, Lange launched into a full-time career as a commercial artist. He developed a thriving business documenting Long Islanders' homes, farms and communities on canvas and also doing promotional scenes for hotels and tourist-related businesses until he moved to Washington State in 1889.