Sayreville is a borough in Middlesex County, New Jersey, United States. Sayreville is within the heart of the Raritan Valley region, located on the south banks of the Raritan River, and also located relatively near the Raritan Bay. As of the 2010 United States Census, the borough's population was 42,704, reflecting an increase of 2,327 (+5.8%) from the 40,377 counted in the 2000 Census, which had in turn increased by 5,391 (+15.4%) from the 34,986 counted in the 1990 Census.
Sayreville was originally incorporated as a township on April 6, 1876, from portions of South Amboy Township. On April 2, 1919, the borough was reincorporated as the Borough of Sayreville and ratified by a referendum held on April 29, 1919.
Native Americans were the first settlers of Sayreville. Tribes of the Navesink lived along the South River where Jernee Mill Road is located today. This was noted on a 1656 New Netherland map by Adriaen van der Donck, a Dutch surveyor and map maker. Attempting to buy land from the Native Americans, European settlers travelled up the Raritan River in 1663. During the 20th century, amateur archaeologists found thousands of Indian artifacts at the location shown on the map.
Predating the incorporation of Sayreville, the Morgan Inn (later known as the Old Spye Inn) was established in 1703 in what is now the Morgan section of Sayreville. Charles Morgan III and his descendants, including Major General James Morgan and Lieutenant Nicholas Morgan, played significant roles in the Revolutionary War. The Morgan family lived in the area for over 200 years and many family members, including Evertsons, are buried in the privately owned Morgan Cemetery, which overlooks Raritan Bay.