South Plainfield is a borough in northern Middlesex County, New Jersey, set within the Raritan Valley region of the New York metropolitan area, on the border with Union County. With a 2020 census population of about 24,300, it is a predominantly residential suburban community surrounded by larger neighbors — Edison and Piscataway to the south and east, Plainfield and Scotch Plains across the Union County line to the north. The borough's location at the intersection of several major road corridors places it squarely within central New Jersey's commuter belt. South Plainfield's history runs deep into the colonial era. The area that became the borough was occupied by British forces from December 1776 through June 1777 during the Revolutionary War, a reminder of the region's central role in the conflict. Through the nineteenth century, the community remained largely agricultural, its landscape shaped by small farms of under two hundred acres. Over the twentieth century, as central New Jersey suburbanized, South Plainfield grew into the established residential borough it is today, with older neighborhoods near its center and newer development toward its edges. The borough functions primarily as a bedroom community. Many residents commute to employment centers in Edison, New Brunswick, and the larger Route 1 and Route 287 corridors, as well as into New York City. South Plainfield supports a mix of local retail and light commercial uses along its main arteries, while its identity centers on neighborhoods, schools, and parks rather than a large downtown. For homebuyers, South Plainfield offers the classic appeal of a Middlesex County suburb: established single-family neighborhoods, a strong local school district, and convenient highway access to the region's employment centers. Spring Lake Park, with its lake, trails, and picnic areas, anchors local recreation, and the borough's proximity to Rutgers University and the amenities of New Brunswick and Edison adds to its everyday convenience.