New Hampshire Route 155 is an 11.259-mile-long (18.120 km) secondary north–south highway in southeastern New Hampshire, almost entirely within Strafford County. The highway runs from New Hampshire Route 125 in Epping to New Hampshire Route 9 in Dover.

New Hampshire Route 125 is a 51.994-mile-long (83.676 km) north–south state highway in Rockingham, Strafford and Carroll counties in southeastern New Hampshire. The southern terminus is in Plaistow at the Massachusetts state line, where the road continues south into Haverhill as Massachusetts Route 125. The northern terminus is in Wakefield at New Hampshire Route 16 and New Hampshire Route 153.