Riverhead  is a community rich in natural, historic, and scenic resources that is experiencing powerful forces of change. Riverhead continues to be the most important agricultural community in Suffolk County and one of the most important in the State. Riverhead's unique landscape also includes waterfront areas on the Great Peconic Bay, Flanders Bay, and Long Island Sound; portions of the Central Pine Barrens and the scenic Peconic River; and distinctive bluffs and woodlands along the Sound. The Town has an historic Main Street and hamlet centers, like Jamesport and Aquebogue.
Riverhead has a distinctive scenic and historic character, comprised of farmland, open space, historic hamlet centers (including downtown Riverhead), historic structures and sites, and unique natural resource areas such as the Pine Barrens.
Riverhead's agricultural industry will continue to play a leading role in the Town's economy and shape the Town's character and way of life.
The natural resources present in Riverhead today—including stream corridors and wetlands, the Central Pine Barrens region, and the aquifer that provides high quality water to the Town — are integral to Riverhead’s long-term health, safety, and well-being, as well as its identity and economic vitality.
Present-day Riverhead was known as Occabank or Aqubogue to the Corchoug Indians who inhabited the area before the arrival of European settlers. The Peconic Bay Estuary provided a reliable food source to the Corchougs and a means of travel to the watershed areas to hunt, fish, and gather plants and berries. Known as Peaconeik, which meant "little place," (where the woodland edges came together to enclose the space), the bay and river system were the location of a number of Native American villages.
Riverhead was established as a center of commerce soon after the white colonization of eastern Long Island began. The first Colonial period structure within the hamlet may well have been one of New York State's first sawmills. Built in 1659 by John Tucker and Joseph Horton, it was situated east of the present Main Street, on Sawmill Creek. The abundance of white oak, among other tree species that were prized for use as ship timbers, more than likely weighed heavily in the selection of the sawmill site. The first permanent settlement in Riverhead likely occurred somewhat later in the seventeenth century. Forty years after Tucker and Horton built their sawmill a second mill was constructed at the center of the community. It was a water-powered fulling mill, also purportedly the first of its type in New York State. The owner, John Parker, built a residence near the mill and that house still stands south of the Peconic River. Parker's daughter, Mary, married William Albertson. Their numerous descendants helped to populate the area and many of them have played important roles in the history of the town.
On March 13, 1792, the New York State Assembly officially separated Southold and Riverhead Towns and created what was then called "River's Head." Riverhead was formed from a large portion of what was known as the "Aquebogue Division" of Southold. The Suffolk County Courthouse and Jail were constructed in Riverhead by James Fanning in 1727. At the time of the separation two mills, "four or five houses," as well as the home of John Griffing, in which the first town meeting was held on April 3, 1792, were located in the hamlet of Riverhead. The 1800 federal census indicates that there were 253 heads of families living in Riverhead Town, an increase over the 105 people present at the time of the formation of the town.
As the seat of county government, Riverhead attracted a variety of businesses and industries. The Peconic River, which flows into Peconic Bay, played a central role in the town's early development. Mills and other industries which made use of the river's energy and water were built during the eighteenth century. Agriculture has also played an important role in the history of the town and county.