ZIP Code 01821

ZIP code 01821 is a five-digit postal code used by the United States Postal Service for addresses in Billerica, Massachusetts. The ZIP lies within Middlesex County. Clocks here follow the America/New_York time zone (UTC-4).

About 31,780 people live in this ZIP code, and the median household income is roughly $100,158 a year. Figures come from the U.S. Census Bureau American Community Survey and are refreshed as new five-year estimates are released.

What you can do with ZIP code 01821

• Write a mailing address: Billerica, MA 01821. The ZIP goes last, after the state abbreviation.
• Check whether a shipping or delivery quote applies to this area — most US carriers price by ZIP code rather than by city.
• Look up the local time zone before scheduling a call — the ZIP tells you which zone applies to that address.
• Compare the ZIP with neighbouring codes to see how population and income shift block by block.