is now Brookhaven was known as Setauket. Founded as a group of agricultural hamlets in the mid-17th century, Brookhaven first expanded as a major center of shipbuilding in the 19th century. Its proximity to New York City facilitated the establishment of resort communities, followed by a post-war population boom. In the 2020 census record, Brookhaven contained 485,773 people.

The township is home to two renowned research centers,