Sayreville, Borough, Middlesex County, eastern New Jersey, on the Raritan River, near Raritan Bay; settled about 1775, incorporated 1920. Manufactures include paints, chemicals, and processed food. The local historical society operates a museum here. Until the 1870s, Sayreville was an important river port.

Originally known as Roundabout (for river bends here) and then as Wood's Landing, it was renamed in the 1870s for James R. Sayre, Jr., a co-owner of a brick company that once flourished here. Extensive clay deposits supported the brick industry from the early 1800s until 1970.

Although the borough remains well-known as an industrial town, the addition of many technology companies and a growing residential population has changed the landscape of this central New Jersey town.