High Quality Content by WIKIPEDIA articles! New Hampshire Route 16 (abbreviated NH 16) is a 149.75-mile (241.00 km) long north–south highway in the U.S. state of New Hampshire. Much of its length is close to the border with Maine. NH 16 is the main route from the Seacoast region north to the Lakes Region and the White Mountains. The section from Portsmouth to Milton is a controlled-access toll highway known as the Spaulding Turnpike. Between the Portsmouth Circle and Dover Point, US 4 is also routed along the Turnpike. The northern section of Route 16 is called the White Mountain Highway.