NH 27 is a local highway which parallels the New Hampshire Route 101 expressway for its entire length.

It proceeds east 1/4 mile and crosses New Hampshire 28 Bypass (Londonderry Turnpike), then continues northeast through Hooksett into Candia.

Turning southeast, the highways run concurrently past the center of Raymond, with NH 107 splitting off to the south in the eastern part of the town.

NH 27 continues east into the town of Epping, where it crosses New Hampshire Route 125 (Calef Highway), a major north–south two-lane highway in eastern New Hampshire.

NH 27 then continues southeast through southern Epping, passing Star Speedway and New England Dragway, and reaches northwest Exeter, where it interchanges with New Hampshire Route 101, the major east–west freeway for the region.