81 ZIP Codes
| Zip Code | City | Population ↓ |
|---|---|---|
| 02148 | Malden | 65,906 |
| 02155 | Medford | 61,730 |
| 02149 | Everett | 50,045 |
| 01801 | Woburn | 41,939 |
| 01752 | Marlborough | 41,647 |
| 02139 | Cambridge | 40,033 |
| 01702 | Framingham | 39,789 |
| 02138 | Cambridge | 38,509 |
| 01852 | Lowell | 37,144 |
| 01760 | Natick | 36,782 |
| 02472 | Watertown | 35,620 |
| 01851 | Lowell | 33,403 |
| 01826 | Dracut | 32,629 |
| 01701 | Framingham | 32,618 |
| 02453 | Waltham | 31,591 |
| 01876 | Tewksbury | 31,004 |
| 01821 | Billerica | 30,143 |
| 01854 | Lowell | 30,081 |
| 02176 | Melrose | 29,650 |
| 02474 | Arlington | 28,642 |
| 01880 | Wakefield | 27,793 |
| 02145 | Somerville | 27,495 |
| 02478 | Belmont | 27,175 |
| 01824 | Chelmsford | 26,650 |
| 01803 | Burlington | 26,274 |
| 01867 | Reading | 25,612 |
| 02143 | Somerville | 25,513 |
| 02144 | Somerville | 25,448 |
| 01886 | Westford | 24,690 |
| 01720 | Acton | 23,526 |
| 01890 | Winchester | 23,406 |
| 02180 | Stoneham | 23,355 |
| 01887 | Wilmington | 23,336 |
| 02140 | Cambridge | 21,204 |
| 01749 | Hudson | 20,077 |
| 01748 | Hopkinton | 19,358 |
| 01776 | Sudbury | 19,270 |
| 01721 | Ashland | 18,873 |
| 02459 | Newton Center | 18,449 |
| 01742 | Concord | 18,448 |
| 02421 | Lexington | 18,080 |
| 01850 | Lowell | 17,740 |
| 02476 | Arlington | 17,708 |
| 02451 | Waltham | 17,393 |
| 02420 | Lexington | 16,215 |
| 02452 | Waltham | 15,808 |
| 01864 | North Reading | 15,765 |
| 01746 | Holliston | 15,094 |
| 01730 | Bedford | 14,707 |
| 02141 | Cambridge | 14,517 |
| 01778 | Wayland | 14,033 |
| 02458 | Newton | 13,050 |
| 01879 | Tyngsboro | 12,550 |
| 01862 | North Billerica | 12,129 |
| 02465 | West Newton | 11,697 |
| 01463 | Pepperell | 11,697 |
| 02493 | Weston | 11,579 |
| 01450 | Groton | 11,356 |
| 01754 | Maynard | 10,712 |
| 01460 | Littleton | 10,280 |
| 02460 | Newtonville | 10,099 |
| 01863 | North Chelmsford | 9,796 |
| 02466 | Auburndale | 8,679 |
| 01432 | Ayer | 8,521 |
| 01775 | Stow | 7,165 |
| 01464 | Shirley | 6,976 |
| 02461 | Newton Highlands | 6,975 |
| 01469 | Townsend | 6,820 |
| 02468 | Waban | 5,773 |
| 01719 | Boxborough | 5,496 |
| 01741 | Carlisle | 5,239 |
| 01773 | Lincoln | 4,891 |
| 02142 | Cambridge | 4,737 |
| 01770 | Sherborn | 4,427 |
| 02464 | Newton Upper Falls | 3,833 |
| 01827 | Dunstable | 3,408 |
| 01431 | Ashby | 3,211 |
| 01474 | West Townsend | 2,280 |
| 01731 | Hanscom Afb | 2,110 |
| 02462 | Newton Lower Falls | 1,470 |
| 01718 | Acton | 404 |
The data shown reflect ZCTAs from the US Census. As of 2025, there are 81 ZCTAs in Middlesex County, Massachusetts (US Census).