Larger cities influence a larger area, don't understand what's difficult to understand about that. NH is included in the Boston MSA in the Census.

Boston is a larger city than Burlington. A good chunk of Fairfield county is an hour north of Manhattan, and I think everyone would call Fairfield county a suburb of NYC. There are also a ton of large employers north of Boston in the Burlington/Andover region like Raytheon, HPE, etc. that makes commuting from NH much easier.