Sag Harbor is an incorporated village in Suffolk County, New York, United States, with parts in both the Towns of East Hampton and Southampton. The population was 2,313 at the 2000 census.

The entire business district of the whaling port and writer's colony is listed as Sag Harbor Village District on the National Register of Historic Places.

Sag Harbor is about three fifths in Southampton and two fifths in East Hampton. The dividing line is Division Street which becomes Town Line Road just south of the village. Most of the defining landmarks of the village—including its Main Street, the Whalers Church, Jermain Library, Whaling Museum, the Old Burying Ground, Oakland Cemetery, Mashashimuet Park, and Otter Pond are all in Southampton. However, almost all the Bay Street marina complex at the foot of Main Street is in East Hampton as are the village's high school, the Sag Harbor State Golf Course, and the freed slave community of Eastville.

The port supplanted the East Hampton community of Northwest which is about five miles east of Sag Harbor. International ships and the whaling industry had started in Northwest but its port was too shallow. The most valuable whale product was whale oil which was used in lamps; thus it could be said that Sag Harbor was a major oil port.

By 1789 Sag Harbor had "had more tons of square-rigged vessels engaged in commerce than even New York City."[3] It had become an international port.

During the American Revolutionary War, American raiders under Return Jonathan Meigs attacked a British garrison on May 23, 1777, on a hill at what today is the Old Burying Ground next to the Whaler's Church, killing six and capturing 90 British soldiers in what was called Meigs Raid.

During the War of 1812, the British attacked the town on July 11, 1813 but were driven back.

The whaling industry in Sag Harbor peaked in the 1840s. Sag Harbor is mentioned in Chapters 12, 13, 57 and 83 of Moby-Dick[4] including this passage:

Arrived at last in old Sag Harbor; and seeing what the sailors did there; and then going on to Nantucket, and seeing how they spent their wages in that place also, poor Queequeg gave it up for lost. Thought he, it's a wicked world in all meridians; I'll die a pagan.[5]

Among the sea captains who died whaling from Sag Harbor was Charles Watson Payne, the great-great-great grandfather of Howard Dean[6] Relics of this period include the Old Whaler's Church which is a Presbyterian Church that sported a 168-foot high steeple which was claimed to be the tallest structure on Long Island when it opened in 1843.[7] The steeple collapsed during the Great Hurricane of 1938 The Masonic Lodge (Wamponamon 437) occupies the handsome, 1840Greek Revival building designed by Minard Lafever The Masonic Lodge is celebrating its 150th anniversary in 2008. The building is now open to the public as the Sag Harbor Whaling Museum, and the staircase and alone is worth a visit. TheArchitecture of both the Whaler's Church & the Masonic Temple are attributed to prominent 19th century American architectMinard LaFever. The broken mast monument in Oakland Cemetery is the most visible of several memorials to those who died at sea. The whaling business collapsed after 1847 initially with the discovery of other methods to create kerosene with the first being coal oil. The discovery of petroleum in Titusville, Pennsylvania in 1859 sealed the end. Many of the ships based in Sag Harbor were sailed to San Francisco, California where they were simply abandoned during the California Gold Rush. The last whaler—the Myra—sailed from Sag Harbor in 1871.[[8]] One sailor who continued on other endeavors was Mercator Cooper who sailed out of Sag Harbor on November 9, 1843 on the Manhattan (1843) on a voyage that would make him the first American to visitTokyo Bay. Aboard the ship was Pyrrhus Concer a former slave who was the first black man the Japanese had seen. Cooper's adventures were to continue on another voyage out of Sag Harbor when on January 26, 1853, sailing the Levant became the first person to set foot on East Antarctica. During World War I the E.W. Bliss Company testedtorpedoes in the harbor a half mile north of Sag Harbor. As part of the process, Long Wharf in Sag Harbor was reinforced with concrete and rail spurs built along the wharf as the torpedoes were loaded onto ships for testing. The torpedoes were shipped via the Long Island Rail Road along the Sag Harbor to the wharf which was owned by the railroad at the time. Among those observing the tests was Thomas Alva Edison. Most of the today's buildings on the wharf including the Bay Street Theatre were built during this time. The torpedoes which did not have live warheads are occasionally found by divers on the bay floor. Various industries have operated in town, the last of which was theBulova Watchcase Factory, which closed in 1981. Sag Harbor was also author John Steinbeck's residence from 1955 until his death in 1968. The Sag Harbor-North HavenBridge is notable as the site of Pop artist Ray Johnson's presumed suicide in 1995 as well as two abortive suicide attempts by monologist Spalding Gray, in September 2002 and October 2003. Sag Harbor is also the birthplace of the noted American poet George Sterling.

“Sag Harbor’s earliest newspapers published little in the way of local news. Concentrating instead on a story, sermon, and both national and international events. It is likely that folks learned all the local gossip and goings on at the general store barber shop, or on the street corner,” wrote noted local historian Dorothy Zaykowski, in her book “Sag Harbor – The Story of an American Beauty.”

It wasn’t until The Corrector was first published in 1822 that Sag Harbor had a well-established community paper. According to Zaykowski, Henry Wentworth Hunt arrived to the village from Boston with his three sons, two of whom went on to helm Sag Harbor papers. The Corrector was published on a weekly basis until 1837, when it became a semi-weekly until Hunt passed away in 1859. After Hunt’s death, his son Alexander and Brinley Sleight took over, publishing the newspaper daily, though this business model proved unsuccessful and the paper reverted back to a weekly publication. The Corrector went on to become the Sag Harbor Corrector.

The Sag Harbor Corrector was eventually purchased by Burton Corwin, owner of the Sag Harbor News, in 1919 and became the Sag Harbor News and Corrector. This amalgamated newspaper was subsequently purchased by the Gardner family, owners of the The Sag Harbor Express, in the late 1920s to become the only Sag Harbor newspaper.[11]