(Links below lead to Quick Facts for Massachusetts Counties: People, Business & Geography at U.S. Census Bureau.)
| Area | 7/1/2009 | 7/1/2008 | 7/1/2007 | 7/1/2006 | 7/1/2005 | 7/1/2004 | 7/1/2003 | 7/1/2002 | 7/1/2001 | 7/1/2000 | Census 2000 |
| Massachusetts | 6,593,587 | 6,543,595 | 6,499,275 | 6,466,399 | 6,453,031 | 6,451,279 | 6,451,637 | 6,440,978 | 6,411,730 | 6,363,015 | 6,349,097 |
|---|---|---|---|---|---|---|---|---|---|---|---|
| Barnstable County | 221,151 | 221,521 | 222,246 | 223,351 | 224,877 | 226,728 | 228,038 | 226,893 | 224,928 | 223,245 | 222,230 |
| Berkshire County | 129,288 | 129,571 | 130,219 | 130,494 | 131,268 | 132,052 | 132,672 | 133,101 | 133,723 | 134,787 | 134,953 |
| Bristol County | 547,433 | 545,810 | 544,487 | 543,634 | 544,688 | 545,460 | 545,819 | 542,717 | 538,299 | 536,008 | 534,678 |
| Dukes County | 15,974 | 15,772 | 15,627 | 15,487 | 15,517 | 15,520 | 15,487 | 15,380 | 15,201 | 15,072 | 14,987 |
| Essex County | 742,582 | 737,365 | 733,066 | 731,174 | 730,256 | 730,901 | 732,303 | 733,096 | 730,782 | 725,379 | 723,419 |
| Franklin County | 71,778 | 71,877 | 71,771 | 71,774 | 71,929 | 71,933 | 71,870 | 71,830 | 71,593 | 71,499 | 71,535 |
| Hampden County | 471,081 | 469,204 | 467,756 | 466,944 | 465,871 | 464,622 | 463,442 | 460,848 | 457,723 | 456,573 | 456,228 |
| Hampshire County | 156,044 | 155,788 | 155,198 | 154,648 | 154,124 | 153,998 | 153,845 | 153,011 | 152,304 | 152,381 | 152,251 |
| Middlesex County | 1,505,006 | 1,487,636 | 1,475,519 | 1,467,985 | 1,465,156 | 1,467,576 | 1,470,427 | 1,473,966 | 1,476,773 | 1,468,934 | 1,465,396 |
| Nantucket County | 11,322 | 11,272 | 11,060 | 10,803 | 10,608 | 10,536 | 10,305 | 10,076 | 9,742 | 9,574 | 9,520 |
| Norfolk County | 666,303 | 661,359 | 656,122 | 652,750 | 650,996 | 652,283 | 652,781 | 654,144 | 653,482 | 651,227 | 650,308 |
| Plymouth County | 498,344 | 494,353 | 491,361 | 489,241 | 488,267 | 486,640 | 485,444 | 483,209 | 478,981 | 474,414 | 472,822 |
| Suffolk County | 753,580 | 742,724 | 728,819 | 715,799 | 712,228 | 710,282 | 711,144 | 711,464 | 705,348 | 691,238 | 689,807 |
| Worcester County | 803,701 | 799,343 | 796,024 | 792,315 | 787,246 | 782,748 | 778,060 | 771,243 | 762,851 | 752,684 | 750,963 |
Source: Population Division, U.S. Census Bureau