Selden is a hamlet (and census-designated place) in the Town of Brookhaven in Suffolk County, New York, United States. The population was 19,851 at the 2010 census.
The farmers who first moved to what is now Selden in the mid-18th century referred to the area as "Westfield" (or sometimes as Westfields). One of the better known early residents was Captain Daniel Roe (1740–1820), who fought in the French and Indian War and served as a captain in the Revolutionary War, and for whom Captain Daniel Roe Highway is named. Roe built a house in Selden along Middle Country Road before the Revolutionary War. Roe is buried in a small family cemetery south of Middle Country Road behind the Old Westfield shopping center.
Roe sided with the Patriots in the lead-up to the Revolutionary War. In the fall of 1776, Roe was assigned to lead a raid against the Tory and Hessian detachment near Selden led by his cousin Richard Miller. Miller was a wanted man, and Roe himself had pledged 10 pounds of the bounty offered for Miller's capture. When Miller rode right by Roe's house in uniform, he was confronted by Roe's men and ordered to dismount. Instead, Miller fired his pistol and turned to flee, whereupon he was shot by the militiamen. Miller was then carried into Roe's house, where he died.
A school district for the Westfield area was first created in 1815, carved out of the districts for New Village (now Centereach) and Coram.