Before the American Revolution, the hamlet had been known as Suffolk County Court House because one had been built, with a jail, in 1727. It had been a long time coming: When Suffolk was established in 1683, the colonial government ordered a court and jail be built to serve both Southold and Southampton. The two towns fought over the location for decades; finally the courthouse went up in the part of Southold that in 1792 split off to become Riverhead, named for its location at the mouth of the Peconic River.
In addition to the courthouse, there were then two mills, the handful of houses and John Griffing’s home-and-tavern in which the early annual town meetings were held. By contrast, Wading River, at the west end of the town, had been settled since 1671 and was a thriving seaport town.
Life was primitive. River water power was important, and several more mills, for cutting logs, grinding grain and finishing cloth, were built in the hamlet. Most unusual was the Riverhead Water Works Tower Mill, which provided water to the community for many years. It was copied after a European castle, and though made of wood was cleverly designed to look as if made of stone. Town CenterFarming was the core family occupation, but Riverhead also produced shoes, harnesses, cigars and coffins. Some Riverheaders were carpenters and later, some became shipbuilders.