| County | Rank | Change (2020) ↓ | 2025 Pop. | 2020 Pop. |
|---|---|---|---|---|
| Hampshire County | 1 | 10.81% | 162,470 | 146,616 |
| Worcester County | 2 | 1.77% | 874,852 | 859,669 |
| Plymouth County | 3 | 1.74% | 539,428 | 530,200 |
| Bristol County | 4 | 1.61% | 586,035 | 576,772 |
| Nantucket County | 5 | 1.47% | 14,446 | 14,237 |
| Barnstable County | 6 | 1.33% | 231,049 | 228,012 |
| Essex County | 7 | 1.17% | 817,269 | 807,791 |
| Norfolk County | 8 | 0.96% | 731,481 | 724,554 |
| Middlesex County | 9 | 0.62% | 1,638,268 | 1,628,235 |
| Dukes County | 10 | -0.29% | 20,533 | 20,593 |
| Franklin County | 11 | -0.57% | 70,518 | 70,923 |
| Hampden County | 12 | -1.07% | 459,357 | 464,311 |
| Berkshire County | 13 | -2.53% | 125,360 | 128,619 |
| Suffolk County | 14 | -3.7% | 767,651 | 797,181 |
Massachusetts's counties show varied growth patterns from 2020 to 2025. Hampshire County leads with 10.81% annualized growth, followed by Worcester County (1.77%) and Plymouth County (1.74%). The largest counties are Middlesex County (1,638,268), Worcester County (874,852), and Essex County (817,269). Of the 14 counties in Massachusetts, 9 are growing while 5 have experienced population decline. Overall, counties averaged 0.95% annualized growth, with total population growing by 0.59% annually.