[2] The southern part of this concurrency forms one of the main commercial districts in Hudson, known as Derry Street.

At Elm Avenue, 3A leaves the concurrency heading west, while 102 continues in a more northeasterly direction along Derry Road.

After leaving Hudson a second time, it enters Londonderry as Nashua Road, passing through a rural area near several farms and apple orchards.

Immediately after the interchange with I-93, Route 102 enters Derry as Broadway, the main commercial thoroughfare in town.

After the intersection with Crystal Avenue (New Hampshire Route 28) at the center of town, it passes the Hoodkroft golf course and meets Main Street (New Hampshire Route 28 Bypass) at a traffic circle at the community of Derry Village.