Massachusetts Population Estimates Program

Population Estimates by County

Each year, the U.S. Census Bureau develops county-level population estimates based on the demographic components of change since the last Census count, including births, deaths, domestic and international migration, and the group quarters population for each county. Their latest county estimates were released on March 22, 2018 for population as of July 1, 2017.

The sections below include information on population change over the past year and cumulatively since the 2010 Census as well as the estimated components of change for the last year and since 2010 for all Massachusetts counties. 

For more information on the U.S. Census Bureau’s Vintage 2017 Population Estimates Release and to see national county data, click here.

For more information on state and sub-county level estimates for Massachusetts, please link to our state population and city/town population pages.

For Massachusetts county-level estimates by age, race, and ethnicity, see the UMDI summary report and related appendices in the Resources and Downloads section at the bottom of this page.

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2017 Census Bureau County Population Estimates for Massachusetts

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According to the new county-level population estimates released by the U.S. Census Bureau, the greatest numerical increases in Massachusetts counties from July 1, 2016 to July 1, 2017 were seen in Middlesex at 8,633 persons gained; Suffolk at 6,774; and Worcester at 5,435.

In terms of percentage change, the largest gains were in Nantucket at 1.3%, Suffolk at 0.9%, and Worcester at 0.7%. Middlesex and Suffolk were also top population gainers last year, while Suffolk and Nantucket were among the three counties with the greatest percentage increase last year. Worcester County regained its status as the third fastest growing county in the state by single-year percentage growth this year, after having been displaced by Plymouth County just the year before.

Suffolk, Middlesex, and Nantucket Counties had the highest rates of international migration in the state in 2017, which helped to boost their population growth over the past year. They also had the highest rates of natural increase from 2016 to 2017, meaning they had the greatest numbers of births over deaths per 1,000 population over the past year as compared to other parts of the state. Worcester County, the third fastest growing county in the state last year, increased population through a combination of low domestic out-migration offset by some international in-migration, combining with positive net natural increase.

The slowest growing counties in the 2016-2017 period were Barnstable, with an estimated increase of just four people, or 0.0%; Dukes, with an increase of 13, or 0.1%; and Franklin, with an increase of 84, or 0.1%. The only county estimated to have lost population over the year was Berkshire, with a decrease of 545 people, or -0.4%.

Map 1. Estimated Population by Massachusetts County, July 1, 2017

Figure description.

Estimated Population by Massachusetts County, July 1, 2017

Citation: UMass Donahue Institute. Annual Estimates of the Resident Population: April 1, 2010 to July 1, 2017. U.S. Census Bureau, Population Division. March 22, 2018.

Map 2. Massachusetts 2017 County Population Estimates: Percent Change July 1, 2016 to July 1, 2017

Figure description.

Massachusetts 2017 County Population Estimates: Percent Change July 1, 2016 to July 1, 2017

Citation: UMass Donahue Institute. Annual Estimates of the Resident Population: April 1, 2010 to July 1, 2017. U.S. Census Bureau, Population Division. March 22, 2018.

Table 1 below shows county population estimates, change, and rankings for July 1, 2016 to July 1, 2017. Data for all counties are available in the downloads section of this page below.

Table 1. Annual Estimates of Resident Population Change and Rankings for Massachusetts Counties July 1, 2016 to July 1, 2017

Table description.

Geographic Area July 1 Population Estimate Change 2016 to 2017 Rank Change 2016 to 2017
2016 2017 Number Percent Number Percent
Massachusetts 6,823,721 6,859,819 36,098 0.5% (X) (X)
Barnstable 213,440 213,444 4 0.0% 13 13
Berkshire 126,858 126,313 -545 -0.4% 14 14
Bristol 558,312 561,483 3,171 0.6% 7 6
Dukes 17,312 17,325 13 0.1% 12 12
Essex 780,633 785,205 4,572 0.6% 4 5
Franklin 70,618 70,702 84 0.1% 11 10
Hampden 469,003 469,818 815 0.2% 8 9
Hampshire 161,658 161,834 176 0.1% 9 11
Middlesex 1,594,314 1,602,947 8,633 0.5% 1 7
Nantucket 11,089 11,229 140 1.3% 10 1
Norfolk 696,818 700,322 3,504 0.5% 5 8
Plymouth 511,820 515,142 3,322 0.6% 6 4
Suffolk 791,165 797,939 6,774 0.9% 2 2
Worcester 820,681 826,116 5,435 0.7% 3 3

Source: Annual Estimates of the Resident Population: April 1, 2010 to July 1, 2017 (PEP_2016_PEPANNRES), U.S. Census Bureau, Population Division, March 22, 2018.

While “single-year change” refers to estimated growth or decline between July 1 of one estimates year to July 1 of the next, “cumulative change” measures the total net change since the last census count date of April 1, 2010.

Map 3. Massachusetts 2017 County Population Estimates: Cumulative Change, Census 2010 to July 1, 2017

Figure description.

Massachusetts 2017 County Population Estimates: Cumulative Change, Census 2010 to July 1, 2017

Source: UMass Donahue Institute. Annual Estimates of the Resident Population: April 1, 2010 to July 1, 2017. U.S. Census Bureau, Population Division. March 22, 2018.

Table 2, below, shows county population estimates, cumulative change, and rankings from the April 1, 2010 base to the July 1, 2017 estimate, while the map above (Map 3) displays the cumulative percentage change for each county from Census 2010 to the July 1, 2017 estimate. According to these estimates, Suffolk County has been growing the fastest, in terms of percentage growth, since the last Census at 10.5%, followed by Nantucket at 10.4% and Middlesex at 6.6%. In numeric terms, Middlesex County led the state, growing by 99,930 persons since 2010, followed by Suffolk at 75,803 and Essex at 42,033.

Table 2. Cumulative Estimates of Resident Population Change and Rankings for Massachusetts Counties April 1, 2010 to July 1, 2017

Table description.

Geographic Area Population Estimates Change 2010 to 2017 Rank Change
April 1, 2010 Estimates Base July 1, 2017 Number Percent By Number By Percent
Massachusetts 6,547,808 6,859,819 312,011 4.8% (X) (X)
Barnstable 215,868 213,444 -2,424 -1.1% 13 13
Berkshire 131,272 126,313 -4,959 -3.8% 14 14
Bristol 548,265 561,483 13,218 2.4% 7 9
Dukes 16,535 17,325 790 4.8% 11 5
Essex 743,172 785,205 42,033 5.7% 3 4
Franklin 71,372 70,702 -670 -0.9% 12 12
Hampden 463,625 469,818 6,193 1.3% 8 11
Hampshire 158,078 161,834 3,756 2.4% 9 10
Middlesex 1,503,017 1,602,947 99,930 6.6% 1 3
Nantucket 10,172 11,229 1,057 10.4% 10 2
Norfolk 670,968 700,322 29,354 4.4% 4 6
Plymouth 494,949 515,142 20,193 4.1% 6 7
Suffolk 722,136 797,939 75,803 10.5% 2 1
Worcester 798,379 826,116 27,737 3.5% 5 8

Source: Annual Estimates of the Resident Population: April 1, 2010 to July 1, 2017 (PEP_2016_PEPANNRES), U.S. Census Bureau, Population Division, March 22, 2018.

County-level estimates are produced by the U.S. Census Bureau using the latest data available for the various components of change, which include births and deaths, domestic migration (within the United States) and international migration, and the group quarters population for each county. The following section describes changes in the Massachusetts county-level population estimates due to births, deaths, and migration.

Natural Increase
Natural increase is the net change in population after births and deaths are added together. The following chart (Figure 1) shows the estimated number of births, deaths, and the resulting net natural increase in each county for the period of July 1, 2016 to July 1, 2017. Note that in counties with a great number of births compared to deaths, such as Middlesex and Suffolk, we see a positive net natural increase and stronger population growth. In counties where the number of deaths outweighs the number of births, such as Barnstable and Berkshire, we see negative values for net natural increase and either very minimal population growth or decline.

Figure 1. 2017 Births, Deaths, and Net Natural Increase by Massachusetts County

Figure description.

2017 Births, Deaths, and Net Natural Increase by Massachusetts County

Source: UMass Donahue Institute. Estimates of the Components of Resident Population Change: April 1, 2010 to July 1, 2017 (PEP_2017_PEPTCOMP). U.S. Census Bureau, Population Division. March 22, 2018.

Migration
In the estimates process, net international migration measures in- and out-migration between a county and places outside the U.S. These numbers represent estimates produced by the U.S. Census Bureau’s analysis of American Community Survey data on the foreign-born population and other data sources. Domestic migration, sometimes called internal migration, measures movement from one county to another within the U.S. To estimate this component, the U.S. Census Bureau uses a combination of IRS data on tax filers and Medicare enrollment data. The sum of these two types of migration, international and domestic, equals the total net migration. The following chart (Figure 2) shows the international, domestic, and total net migration estimates for each Massachusetts county for the period of July 1, 2016 to July 1, 2017. Note that most Massachusetts counties—11 out of 14—show negative domestic migration, meaning populations have moved from these counties to other counties within the U.S. However, in all counties except Berkshire and Dukes, the negative domestic migration is offset by greater international immigration—sometimes to a very significant degree, as seen in Worcester, Essex, Middlesex, Suffolk, and Norfolk counties, for example.

Note that the fastest growing counties in the state – Suffolk, Nantucket, Middlesex, and Essex - all share in positive international migration off-setting domestic outmigration in combination with a relatively large number of births over deaths.

Figure 2. 2017 Domestic, International, and Total Net Migration by Massachusetts County

Figure description.

2017 Domestic, International, and Total Net Migration by Massachusetts County

Source: UMass Donahue Institute. Estimates of the Components of Resident Population Change: April 1, 2010 to July 1, 2017 (PEP_2017_PEPTCOMP). U.S. Census Bureau, Population Division. March 22, 2018.

As described above, component data on births, deaths, domestic migration, and international migration combine together (along with group quarters updates and a “residual” component, not shown) to factor into population change for each county. The following tables show the change in each of these components for each county. Table 3 shows single-year change from July 1, 2016 to July 1, 2017, while Table 4 displays this change as average rates per 1,000 persons.

Table 3. Annual Estimates of the Components of Population Change: July 1, 2016 to July 1, 2017

Table description.

Massachusetts County Total Population Change [1] Vital Events Net Migration
Natural Increase Births Deaths Total International [2] Domestic
Barnstable 4 -1,313 1,519 2,832 1,330 307 1,023
Berkshire -545 -375 1,012 1,387 -165 288 -453
Bristol 3,171 356 5,627 5,271 2,849 1,583 1,266
Dukes 13 24 162 138 -9 2 -11
Essex 4,572 1,670 8,430 6,760 2,917 5,325 -2,408
Franklin 84 -93 588 681 182 194 -12
Hampden 815 659 5,004 4,345 149 3,101 -2,952
Hampshire 176 -215 1,016 1,231 391 847 -456
Middlesex 8,633 5,491 17,193 11,702 3,132 13,269 -10,137
Nantucket 140 111 165 54 29 84 -55
Norfolk 3,504 1,340 7,240 5,900 2,182 3,676 -1,494
Plymouth 3,322 523 5,211 4,688 2,832 1,480 1,352
Suffolk 6,774 4,232 9,391 5,159 2,562 10,973 -8,411
Worcester 5,435 1,639 8,610 6,971 3,828 4,169 -341

[1] Total population change includes a residual. This residual represents the change in population that cannot be attributed to any specific demographic component. See Population Estimates Terms and Definitions at http://www.census.gov/popest/about/terms.html. [2] Net international migration (except for Puerto Rico) includes the international migration of both native and foreign-born populations. For population estimates methodology statements, see http://www.census.gov/popest/methodology/index.html.

Source: UMass Donahue Institute. CO-EST2017_ALLDATA. U.S. Census Bureau, Population Division. March 22, 2018.

Table 4. Estimated Annual Rates* of the Components of Population Change for Single Year July 1, 2016 to July 1, 2017

Table description.

Massachusetts County Total Population Change [1] Vital Events Net Migration
Natural Increase Births Deaths Total International [2] Domestic
Barnstable 0.1 -6.2 7.1 13.3 6.2 1.4 4.8
Berkshire -4.3 -3.0 8.0 11.0 -1.3 2.3 -3.6
Bristol 5.7 0.6 10.1 9.4 5.1 2.8 2.3
Dukes 0.9 1.4 9.4 8.0 -0.5 0.1 -0.6
Essex 5.9 2.1 10.8 8.6 3.7 6.8 -3.1
Franklin 1.3 -1.3 8.3 9.6 2.6 2.7 -0.2
Hampden 1.7 1.4 10.7 9.3 0.3 6.6 -6.3
Hampshire 1.1 -1.3 6.3 7.6 2.4 5.2 -2.8
Middlesex 5.4 3.4 10.8 7.3 2.0 8.3 -6.3
Nantucket 12.5 9.9 14.8 4.8 2.6 7.5 -4.9
Norfolk 5.0 1.9 10.4 8.4 3.1 5.3 -2.1
Plymouth 6.5 1.0 10.1 9.1 5.5 2.9 2.6
Suffolk 8.6 5.3 11.8 6.5 3.2 13.8 -10.6
Worcester 6.6 2.0 10.5 8.5 4.6 5.1 -0.4

*Rates per 1,000 average population.
UMass Donahue Institute. Source data: U.S. Census Bureau CO-EST2016_ALLDATA. Release date: March 22, 2018

As described above, component data on births, deaths, domestic migration, and international migration combine together (along with group quarters updates and a “residual” component) to factor into population change for each county. Tables in this section show the cumulative totals for components of change, by county, for the period since 2010. Table 5 shows cumulative components from April 1, 2010 to July 1, 2017, while Table 6 displays the average rates per 1,000 persons over the same period.

Table 5. Cumulative Estimates of the Components of Population Change: April 1, 2010 to July 1, 2017

Table description.

Massachusetts County Total Population Change [1] Vital Events Net Migration
Natural Increase Births Deaths Total International [2] Domestic
Barnstable -2,424 -9,345 11,326 20,671 7,104 2,173 4,931
Berkshire -4,959 -2,580 7,882 10,462 -2,325 1,699 -4,024
Bristol 13,218 3,852 41,213 37,361 9,809 9,529 280
Dukes 790 145 1,161 1,016 643 7 636
Essex 42,033 14,246 61,278 47,032 28,395 33,451 -5,056
Franklin -670 -501 4,452 4,953 -134 1,177 -1,311
Hampden 6,193 6,604 38,148 31,544 -329 20,546 -20,875
Hampshire 3,756 -1,021 7,817 8,838 4,707 5,473 -766
Middlesex 99,930 45,987 126,845 80,858 55,092 86,894 -31,802
Nantucket 1,057 620 1,065 445 425 513 -88
Norfolk 29,354 11,327 52,516 41,189 18,514 23,978 -5,464
Plymouth 20,193 5,534 37,309 31,775 15,075 9,818 5,257
Suffolk 75,803 34,296 68,574 34,278 41,738 69,986 -28,248
Worcester 27,737 13,553 62,875 49,322 14,604 27,022 -12,418

[1] Total population change includes a residual. This residual represents the change in population that cannot be attributed to any specific demographic component. See Population Estimates Terms and Definitions at http://www.census.gov/popest/about/terms.html. [2] Net international migration (except for Puerto Rico) includes the international migration of both native and foreign-born populations. For population estimates methodology statements, see http://www.census.gov/popest/methodology/index.html.

Source: UMass Donahue Institute. CO-EST2017_ALLDATA. U.S. Census Bureau, Population Division. March 22, 2018.

Table 6. Average Estimated Rates* of the Components of Population Change for April 1, 2010 to July 1, 2017

Table description.

Massachusetts County Total Population Change [1] Vital Events Net Migration
Natural Increase Births Deaths Total International [2] Domestic
Barnstable -1.5 -6.1 7.2 13.3 4.5 1.4 3.2
Berkshire -5.5 -2.8 8.4 11.3 -2.6 1.9 -4.5
Bristol 3.3 0.9 10.2 9.3 2.4 2.4 0.0
Dukes 6.3 1.0 9.4 8.3 5.3 0.0 5.3
Essex 7.5 2.5 11.0 8.5 5.0 6.1 -1.0
Franklin -1.2 -1.0 8.6 9.7 -0.2 2.3 -2.5
Hampden 1.7 1.9 11.2 9.3 -0.2 6.1 -6.3
Hampshire 2.3 -0.9 6.7 7.6 3.2 4.7 -1.5
Middlesex 8.9 4.0 11.2 7.2 4.9 7.7 -2.8
Nantucket 14.1 7.8 13.7 5.9 6.3 6.7 -0.4
Norfolk 5.8 2.2 10.5 8.3 3.5 4.8 -1.3
Plymouth 5.5 1.5 10.2 8.7 4.1 2.7 1.4
Suffolk 13.7 6.2 12.4 6.2 7.5 12.7 -5.2
Worcester 4.6 2.2 10.7 8.4 2.4 4.6 -2.3

*Rates per 1,000 average population.

[1] Total population change includes a residual. This residual represents the change in population that cannot be attributed to any specific demographic component. See Population Estimates Terms and Definitions at http://www.census.gov/popest/about/terms.html. [2] Net international migration (except for Puerto Rico) includes the international migration of both native and foreign-born populations. For population estimates methodology statements, see http://www.census.gov/popest/methodology/index.html.

Source: UMass Donahue Institute. CO-EST2017_ALLDATA. U.S. Census Bureau, Population Division. March 22, 2018.

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