| | Essex County | MA | 25009 | Cambridge-Newton-Framingham,
MA 15764 | Boston-Cambridge-Newton,
MA-NH 14460 | Boston-Worcester-Providence,
MA-RI-NH-CT 148 | Central | metro county (urban) | nonspecialized | https://maps.google.com/?q=EssexCounty+MA |
| | Middlesex County | MA | 25017 | Cambridge-Newton-Framingham,
MA 15764 | Boston-Cambridge-Newton,
MA-NH 14460 | Boston-Worcester-Providence,
MA-RI-NH-CT 148 | Central | metro county (urban) | nonspecialized | https://maps.google.com/?q=MiddlesexCounty+MA |