 Route 108 begins at an intersection with Route 110 north of downtown Haverhill, Massachusetts, near Kenoza Lake.The highway proceeds due north, passing underneath I-495 before crossing into Plaistow, New Hampshire, where it becomes NH 108.NH 108 runs along the eastern edge of Plaistow, near the Massachusetts border, before crossing through Newton into East Kingston, where it crosses NH 107A, then turns eastward to form a brief wrong-way concurrency with NH 107.