Question: What was the population of the town as of 2010 in Rockingham County through which New Hampshire Route 121 winds through?
Sentence (from "New Hampshire Route 121"): The southern terminus of NH 121 is at the Massachusetts state line in Plaistow, where the road, named Atkinson Depot Road, continues into the city of Haverhill as an unnumbered local road (North Main Street) leading to Route 125.
Relevant evidence: No