FYI: March 17th is Evacuation Day in Boston, but not all of Massachusetts. Only Boston and the other communities in Suffolk County (Revere, Chelsea, and Winthrop) also observe it.
While State offices in Boston and Suffolk County are closed, I believe they're open everywhere else in Massachusetts, with employees getting a day off they can use at a later date of their choosing.
Very few private-sector workers get the day off.