65 cities
| City | Rank | 2026 Pop. ↓ | 2020 Pop. | Annual Change | Density | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Cambridge | 1 | 124,928 | 118,204 | 1.52% | 19,529 | 6 | City |
| Lowell | 2 | 122,948 | 115,834 | 1.04% | 9,034 | 14 | City |
| Lowell | 3 | 122,710 | 115,834 | 0.94% | 9,016 | 14 | City |
| Cambridge | 4 | 122,677 | 118,204 | 0.61% | 19,177 | 6 | City |
| Newton | 5 | 93,578 | 88,853 | 1.56% | 5,249 | 18 | City |
| Newton | 6 | 91,623 | 88,853 | 0.51% | 5,139 | 18 | City |
| Somerville | 7 | 83,967 | 80,901 | 1.09% | 20,366 | 4 | City |
| Somerville | 8 | 82,773 | 80,901 | 0.38% | 20,076 | 4 | City |
| Framingham | 9 | 74,835 | 72,129 | 0.99% | 2,988 | 25 | City |
| Framingham | 10 | 73,977 | 72,129 | 0.42% | 2,954 | 25 | City |
| Malden | 11 | 68,399 | 66,086 | 1.26% | 13,558 | 5 | City |
| Waltham | 12 | 67,217 | 64,238 | 1.03% | 5,274 | 13 | City |
| Malden | 13 | 66,996 | 66,086 | 0.23% | 13,280 | 5 | City |
| Waltham | 14 | 66,654 | 64,238 | 0.61% | 5,230 | 13 | City |
| Medford | 15 | 60,904 | 59,520 | 0.83% | 7,521 | 8 | City |
| Medford | 16 | 60,087 | 59,520 | 0.16% | 7,420 | 8 | City |
| Everett | 17 | 53,779 | 48,957 | 1.85% | 15,743 | 3 | City |
| Everett | 18 | 53,259 | 48,957 | 1.36% | 15,591 | 3 | City |
| Arlington | 19 | 48,102 | 46,202 | 1.04% | 9,355 | 5 | Town |
| Woburn | 20 | 47,519 | 40,827 | 3.96% | 3,756 | 13 | City |
| Woburn | 21 | 45,429 | 40,827 | 1.72% | 3,591 | 13 | City |
| Billerica | 22 | 44,952 | 41,842 | 2.24% | 1,758 | 26 | Town |
| Marlborough | 23 | 42,939 | 41,685 | 0.9% | 2,058 | 21 | City |
| Marlborough | 24 | 42,411 | 41,685 | 0.29% | 2,033 | 21 | City |
| Natick | 25 | 38,128 | 36,924 | 1.08% | 2,549 | 15 | Town |
| Chelmsford | 26 | 37,667 | 36,383 | 0.96% | 1,683 | 22 | Town |
| Lexington | 27 | 35,637 | 34,413 | 1.27% | 2,169 | 16 | Town |
| Dracut | 28 | 33,642 | 32,529 | 1.01% | 1,627 | 21 | Town |
| Tewksbury | 29 | 32,522 | 31,132 | 1.13% | 1,569 | 21 | Town |
| Wakefield | 30 | 31,428 | 27,070 | 3.65% | 4,250 | 7 | Town |
| Melrose | 31 | 30,468 | 29,740 | 0.88% | 6,506 | 5 | City |
| Melrose | 32 | 30,037 | 29,740 | 0.17% | 6,414 | 5 | City |
| Belmont | 33 | 27,960 | 27,235 | 0.93% | 6,017 | 5 | Town |
| Burlington | 34 | 27,625 | 26,002 | 1.19% | 2,351 | 12 | Town |
| Stoneham | 35 | 27,454 | 23,187 | 5.58% | 4,563 | 6 | Town |
| Reading | 36 | 26,729 | 25,536 | 1.3% | 2,679 | 10 | Town |
| Westford | 37 | 25,620 | 24,698 | 1.18% | 847 | 30 | Town |
| Acton | 38 | 25,053 | 23,964 | 1.04% | 1,261 | 20 | Town |
| Wilmington | 39 | 24,612 | 23,302 | 1.67% | 1,450 | 17 | Town |
| Winchester | 40 | 24,491 | 22,929 | 1.11% | 4,060 | 6 | Town |
| Hudson | 41 | 20,822 | 20,029 | 1.11% | 1,806 | 12 | Town |
| Hopkinton | 42 | 20,635 | 18,762 | 1.64% | 787 | 26 | Town |
| Ashland | 43 | 20,589 | 18,836 | 3% | 1,669 | 12 | Town |
| Sudbury | 44 | 20,231 | 18,876 | 1.06% | 834 | 24 | Town |
| Concord | 45 | 17,730 | 18,364 | -1.01% | 723 | 25 | Town |
| North Reading | 46 | 17,401 | 15,512 | 3.03% | 1,323 | 13 | Town |
| Holliston | 47 | 15,643 | 14,988 | 0.96% | 839 | 19 | Town |
| Bedford | 48 | 15,269 | 14,675 | 1.04% | 1,118 | 14 | Town |
| Wayland | 49 | 14,330 | 13,926 | 0.97% | 952 | 15 | Town |
| Tyngsborough | 50 | 13,117 | 12,400 | 1.31% | 781 | 17 | Town |
| Pepperell | 51 | 12,157 | 11,571 | 1.17% | 539 | 23 | Town |
| Weston | 52 | 12,067 | 11,141 | 1% | 717 | 17 | Town |
| Groton | 53 | 11,880 | 11,324 | 1.28% | 362 | 33 | Town |
| Maynard | 54 | 11,016 | 10,729 | 0.9% | 2,114 | 5 | Town |
| Littleton | 55 | 10,773 | 10,131 | 1.31% | 652 | 17 | Town |
| Townsend | 56 | 9,436 | 9,107 | 1.16% | 289 | 33 | Town |
| Ayer | 57 | 9,396 | 8,481 | 2.1% | 1,050 | 9 | Town |
| Stow | 58 | 7,683 | 7,157 | 2.32% | 444 | 17 | Town |
| Shirley | 59 | 7,296 | 7,233 | 1.77% | 461 | 16 | Town |
| Lincoln | 60 | 7,098 | 6,977 | 0.72% | 499 | 14 | Town |
| Boxborough | 61 | 5,673 | 5,495 | 0.96% | 552 | 10 | Town |
| Carlisle | 62 | 5,455 | 5,233 | 1.28% | 357 | 15 | Town |
| Sherborn | 63 | 4,591 | 4,394 | 1.17% | 291 | 16 | Town |
| Dunstable | 64 | 3,610 | 3,362 | 1.55% | 219 | 16 | Town |
| Ashby | 65 | 3,352 | 3,184 | 1.24% | 142 | 24 | Town |
Cambridge is the largest city in Middlesex County, with a population of 124,928.
Ashby is the smallest city in Middlesex County, with a population of 3,352.
There are 65 cities in Middlesex County, Massachusetts.