US 206 enters Montgomery Township in Somerset County, where the name of the road becomes Van Horne Memorial Highway. In Montgomery Township, the route runs to the east of Princeton Airport and crosses CR 518. Following this intersection, CR 533 splits from US 206 by heading northeast, and US 206 continues north-northwest through a mix of suburban and rural areas. The road passes through the community of Harlingen before widening to four lanes and reaching Belle Mead. In this area, US 206 passes over CSX’s Trenton Subdivision before making a turn to the northeast and then to the north, narrowing back to two lanes. The road enters Hillsborough Township, where the Van Horne Memorial Highway designation ends. It crosses an abandoned railroad line leading to the Belle Mead General Depot before continuing into residential and commercial areas of Hillsborough. The road comes to a junction with CR 514 in this area.