65 cities
| City | Rank | 2025 Pop. ↓ | 2020 Pop. | Annual Change | Density | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Cambridge | 1 | 123,057 | 118,204 | 1.54% | 19,237 | 6 | City |
| Cambridge | 2 | 121,931 | 118,204 | 0.61% | 19,061 | 6 | City |
| Lowell | 3 | 121,683 | 115,834 | 1.05% | 8,941 | 14 | City |
| Lowell | 4 | 121,564 | 115,834 | 0.95% | 8,932 | 14 | City |
| Newton | 5 | 92,139 | 88,853 | 1.59% | 5,168 | 18 | City |
| Newton | 6 | 91,161 | 88,853 | 0.51% | 5,113 | 18 | City |
| Somerville | 7 | 83,058 | 80,901 | 1.11% | 20,145 | 4 | City |
| Somerville | 8 | 82,461 | 80,901 | 0.38% | 20,000 | 4 | City |
| Framingham | 9 | 74,098 | 72,129 | 1% | 2,959 | 25 | City |
| Framingham | 10 | 73,669 | 72,129 | 0.42% | 2,942 | 25 | City |
| Malden | 11 | 67,546 | 66,086 | 1.28% | 13,389 | 5 | City |
| Malden | 12 | 66,844 | 66,086 | 0.23% | 13,250 | 5 | City |
| Waltham | 13 | 66,533 | 64,238 | 1.04% | 5,220 | 13 | City |
| Waltham | 14 | 66,251 | 64,238 | 0.61% | 5,198 | 13 | City |
| Medford | 15 | 60,401 | 59,520 | 0.84% | 7,459 | 8 | City |
| Medford | 16 | 59,992 | 59,520 | 0.16% | 7,408 | 8 | City |
| Everett | 17 | 52,802 | 48,957 | 1.89% | 15,457 | 3 | City |
| Everett | 18 | 52,542 | 48,957 | 1.38% | 15,381 | 3 | City |
| Arlington | 19 | 47,607 | 46,202 | 1.05% | 9,258 | 5 | Town |
| Woburn | 20 | 45,707 | 40,827 | 4.13% | 3,613 | 13 | City |
| Woburn | 21 | 44,662 | 40,827 | 1.75% | 3,531 | 13 | City |
| Billerica | 22 | 43,965 | 41,842 | 2.3% | 1,719 | 26 | Town |
| Marlborough | 23 | 42,554 | 41,685 | 0.91% | 2,040 | 21 | City |
| Marlborough | 24 | 42,290 | 41,685 | 0.29% | 2,027 | 21 | City |
| Natick | 25 | 37,722 | 36,924 | 1.09% | 2,522 | 15 | Town |
| Chelmsford | 26 | 37,310 | 36,383 | 0.97% | 1,667 | 22 | Town |
| Lexington | 27 | 35,190 | 34,413 | 1.29% | 2,141 | 16 | Town |
| Dracut | 28 | 33,307 | 32,529 | 1.02% | 1,611 | 21 | Town |
| Tewksbury | 29 | 32,159 | 31,132 | 1.14% | 1,552 | 21 | Town |
| Wakefield | 30 | 30,322 | 27,070 | 3.79% | 4,101 | 7 | Town |
| Melrose | 31 | 30,203 | 29,740 | 0.89% | 6,449 | 5 | City |
| Melrose | 32 | 29,987 | 29,740 | 0.16% | 6,403 | 5 | City |
| Belmont | 33 | 27,701 | 27,235 | 0.94% | 5,961 | 5 | Town |
| Burlington | 34 | 27,301 | 26,002 | 1.2% | 2,323 | 12 | Town |
| Reading | 35 | 26,385 | 25,536 | 1.32% | 2,645 | 10 | Town |
| Stoneham | 36 | 26,002 | 23,187 | 5.91% | 4,322 | 6 | Town |
| Westford | 37 | 25,322 | 24,698 | 1.19% | 837 | 30 | Town |
| Acton | 38 | 24,796 | 23,964 | 1.05% | 1,248 | 20 | Town |
| Winchester | 39 | 24,222 | 22,929 | 1.12% | 4,016 | 6 | Town |
| Wilmington | 40 | 24,207 | 23,302 | 1.7% | 1,426 | 17 | Town |
| Hudson | 41 | 20,593 | 20,029 | 1.12% | 1,786 | 12 | Town |
| Hopkinton | 42 | 20,303 | 18,762 | 1.66% | 774 | 26 | Town |
| Sudbury | 43 | 20,018 | 18,876 | 1.08% | 825 | 24 | Town |
| Ashland | 44 | 19,990 | 18,836 | 3.09% | 1,620 | 12 | Town |
| Concord | 45 | 17,911 | 18,364 | -1% | 731 | 25 | Town |
| North Reading | 46 | 16,890 | 15,512 | 3.12% | 1,284 | 13 | Town |
| Holliston | 47 | 15,495 | 14,988 | 0.96% | 831 | 19 | Town |
| Bedford | 48 | 15,112 | 14,675 | 1.05% | 1,106 | 14 | Town |
| Wayland | 49 | 14,192 | 13,926 | 0.98% | 943 | 15 | Town |
| Tyngsborough | 50 | 12,948 | 12,400 | 1.32% | 771 | 17 | Town |
| Pepperell | 51 | 12,017 | 11,571 | 1.18% | 532 | 23 | Town |
| Weston | 52 | 11,947 | 11,141 | 1.01% | 710 | 17 | Town |
| Groton | 53 | 11,730 | 11,324 | 1.3% | 358 | 33 | Town |
| Maynard | 54 | 10,918 | 10,729 | 0.91% | 2,095 | 5 | Town |
| Littleton | 55 | 10,634 | 10,131 | 1.32% | 644 | 17 | Town |
| Townsend | 56 | 9,328 | 9,107 | 1.17% | 285 | 33 | Town |
| Ayer | 57 | 9,203 | 8,481 | 2.14% | 1,028 | 9 | Town |
| Stow | 58 | 7,509 | 7,157 | 2.37% | 433 | 17 | Town |
| Shirley | 59 | 7,169 | 7,233 | 1.8% | 453 | 16 | Town |
| Lincoln | 60 | 7,047 | 6,977 | 0.73% | 495 | 14 | Town |
| Boxborough | 61 | 5,619 | 5,495 | 0.97% | 546 | 10 | Town |
| Carlisle | 62 | 5,386 | 5,233 | 1.3% | 353 | 15 | Town |
| Sherborn | 63 | 4,538 | 4,394 | 1.18% | 287 | 16 | Town |
| Dunstable | 64 | 3,555 | 3,362 | 1.57% | 216 | 16 | Town |
| Ashby | 65 | 3,311 | 3,184 | 1.25% | 140 | 24 | Town |
Cambridge is the largest city in Middlesex County, with a population of 123,057.
Ashby is the smallest city in Middlesex County, with a population of 3,311.
There are 65 cities in Middlesex County, Massachusetts.