Route 18 is a 42.8-mile-long (68.9 km) state highway in the central part of the US state of New Jersey. It begins at an intersection with Route 138 in Wall Township, Monmouth County and ends at Interstate 287 (I-287) in Piscataway Township, Middlesex County. Route 18 is a major route through central New Jersey that connects the Jersey Shore to the Raritan Valley region, connecting the county seats of Monmouth (Freehold) and Middlesex (New Brunswick) respectively. The route runs through Ocean Township, Marlboro Township, and East Brunswick, as for much of the route is a limited-access freeway (including the entire portion in Monmouth County and much of the northern end through New Brunswick and Piscataway). The remainder of the route is a multi-lane divided highway with traffic lights in th