sentences:  North of Route 80, the road becomes known as Higganum Road, intersecting with Route 148 north of the town center before crossing into the town of Haddam.In Haddam, Route 81 is known as Killingworth Road and has an interchange with Route 9 at Exit 9 before ending at an intersection with Route 154 in the village of Higganum.In the 19th century, the road connecting the villages of Clinton, Killingworth, and Higganum was a private turnpike known as the Killingworth and Haddam Turnpike.