81 zips
| Zip Code | City | Population ↓ |
|---|---|---|
| 02148 | Malden | 65,509 |
| 02155 | Medford | 61,276 |
| 02149 | Everett | 49,236 |
| 01752 | Marlborough | 41,398 |
| 01801 | Woburn | 41,205 |
| 01702 | Framingham | 39,761 |
| 02139 | Cambridge | 39,609 |
| 02138 | Cambridge | 38,077 |
| 01852 | Lowell | 36,700 |
| 01760 | Natick | 36,520 |
| 02472 | Watertown | 35,317 |
| 01826 | Dracut | 32,373 |
| 01851 | Lowell | 32,308 |
| 01701 | Framingham | 32,270 |
| 01876 | Tewksbury | 30,962 |
| 02453 | Waltham | 30,314 |
| 01821 | Billerica | 30,203 |
| 02176 | Melrose | 29,488 |
| 01854 | Lowell | 28,808 |
| 02474 | Arlington | 28,283 |
| 02145 | Somerville | 27,929 |
| 01880 | Wakefield | 27,258 |
| 02478 | Belmont | 26,966 |
| 01824 | Chelmsford | 26,628 |
| 01803 | Burlington | 26,068 |
| 01867 | Reading | 25,474 |
| 02143 | Somerville | 25,161 |
| 02144 | Somerville | 25,009 |
| 01886 | Westford | 24,584 |
| 01720 | Acton | 23,322 |
| 01887 | Wilmington | 23,195 |
| 02180 | Stoneham | 22,986 |
| 01890 | Winchester | 22,862 |
| 02140 | Cambridge | 21,361 |
| 01749 | Hudson | 19,959 |
| 01776 | Sudbury | 19,067 |
| 01748 | Hopkinton | 19,050 |
| 01721 | Ashland | 18,694 |
| 02459 | Newton Center | 18,604 |
| 01742 | Concord | 18,337 |
| 02451 | Waltham | 18,153 |
| 02421 | Lexington | 17,798 |
| 02476 | Arlington | 17,732 |
| 01850 | Lowell | 16,983 |
| 02420 | Lexington | 16,287 |
| 02452 | Waltham | 16,173 |
| 01864 | North Reading | 15,634 |
| 01746 | Holliston | 14,964 |
| 02141 | Cambridge | 14,677 |
| 01730 | Bedford | 14,478 |
| 01778 | Wayland | 13,915 |
| 02458 | Newton | 13,308 |
| 01879 | Tyngsboro | 12,435 |
| 01862 | North Billerica | 11,703 |
| 01463 | Pepperell | 11,693 |
| 02493 | Weston | 11,443 |
| 02465 | West Newton | 11,297 |
| 01450 | Groton | 11,228 |
| 01754 | Maynard | 10,663 |
| 01460 | Littleton | 10,150 |
| 02460 | Newtonville | 10,033 |
| 01863 | North Chelmsford | 9,592 |
| 02466 | Auburndale | 8,553 |
| 01432 | Ayer | 8,124 |
| 01775 | Stow | 7,109 |
| 01464 | Shirley | 7,017 |
| 01469 | Townsend | 6,803 |
| 02461 | Newton Highlands | 6,717 |
| 02468 | Waban | 5,901 |
| 01719 | Boxborough | 5,468 |
| 01773 | Lincoln | 5,257 |
| 01741 | Carlisle | 5,209 |
| 01770 | Sherborn | 4,404 |
| 02142 | Cambridge | 4,349 |
| 02464 | Newton Upper Falls | 3,730 |
| 01827 | Dunstable | 3,375 |
| 01431 | Ashby | 3,188 |
| 01474 | West Townsend | 2,249 |
| 01731 | Hanscom Afb | 1,745 |
| 02462 | Newton Lower Falls | 1,459 |
| 01718 | Acton | 528 |
The data shown reflect ZCTAs from the US Census. As of 2024, there are 81 ZCTAs in Middlesex County, Massachusetts (US Census).