Data / Rankings / Uninsured rate, ages 18 to 64 (US model-based estimate) / Counties in Massachusetts

Counties in Massachusetts by uninsured rate, ages 18 to 64 (US model-based estimate)

Nantucket County had the highest uninsured rate, ages 18 to 64 (US model-based estimate) of 14 counties in 2021, at 4.8%. Norfolk County had the lowest, at 2.9%. The median was 3.7% and the figure for Massachusetts was 3.5%. Source: the U.S. Census Bureau.

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Highest4.8Nantucket County
Lowest2.9Norfolk County
Median3.714 counties
Massachusetts3.5History

Map of counties, 2021

Barnstable County: 3.7 %Berkshire County: 3.7 %Bristol County: 4.3 %Dukes County: 4.7 %Essex County: 3.8 %Franklin County: 3.3 %Hampden County: 4.5 %Hampshire County: 2.9 %Middlesex County: 2.9 %Nantucket County: 4.8 %Norfolk County: 2.9 %Plymouth County: 3.3 %Suffolk County: 3.8 %Worcester County: 3.7 %
  • Under 3.1
  • 3.1 to 3.7
  • 3.7 to 3.8
  • 3.8 to 4.4
  • 4.4 and over
%, 2021. Source: U.S. Census Bureau, Small Area Health Insurance Estimates (SAHIE): percent uninsured, ages 18 to 64, all races, both sexes, all income levels, states and counties. Boundaries: U.S. Census Bureau cartographic boundary files.

All counties, 2021

Nantucket County: 4.8 %Nantucket County4.8Dukes County: 4.7 %Dukes County4.7Hampden County: 4.5 %Hampden County4.5Bristol County: 4.3 %Bristol County4.3Essex County: 3.8 %Essex County3.8Suffolk County: 3.8 %Suffolk County3.8Barnstable County: 3.7 %Barnstable County3.7Berkshire County: 3.7 %Berkshire County3.7Worcester County: 3.7 %Worcester County3.7Franklin County: 3.3 %Franklin County3.3Plymouth County: 3.3 %Plymouth County3.3Hampshire County: 2.9 %Hampshire County2.9Middlesex County: 2.9 %Middlesex County2.9Norfolk County: 2.9 %Norfolk County2.9Nantucket County: 4.8 %Nantucket County4.8Dukes County: 4.7 %Dukes County4.7Hampden County: 4.5 %Hampden County4.5Bristol County: 4.3 %Bristol County4.3Essex County: 3.8 %Essex County3.8Suffolk County: 3.8 %Suffolk County3.8Barnstable County: 3.7 %Barnstable County3.7Berkshire County: 3.7 %Berkshire County3.7Worcester County: 3.7 %Worcester County3.7Franklin County: 3.3 %Franklin County3.3Plymouth County: 3.3 %Plymouth County3.3Hampshire County: 2.9 %Hampshire County2.9Middlesex County: 2.9 %Middlesex County2.9Norfolk County: 2.9 %Norfolk County2.9
%. Source: U.S. Census Bureau, Small Area Health Insurance Estimates (SAHIE): percent uninsured, ages 18 to 64, all races, both sexes, all income levels, states and counties. Retrieved 2026-10-12.

Full ranking

RankCounties2021 (%)Change on 2020
1Nantucket County4.8-0.5 pts
2Dukes County4.7-0.9 pts
3Hampden County4.5+0.1 pts
4Bristol County4.3-0.1 pts
5Essex County3.8-0.4 pts
5Suffolk County3.8-0.3 pts
7Barnstable County3.70 pts
7Berkshire County3.70 pts
7Worcester County3.7+0.4 pts
10Franklin County3.3-0.2 pts
10Plymouth County3.3+0.1 pts
12Hampshire County2.9-0.2 pts
12Middlesex County2.9-0.5 pts
12Norfolk County2.9+0.3 pts

Other periods

About this ranking

People aged 18 to 64 without health insurance coverage of any kind, as a percentage of all people aged 18 to 64. United States: Census Bureau Small Area Health Insurance Estimates (SAHIE) for states and counties, all races, both sexes and all income levels.

A model-based single-year estimate that combines the American Community Survey with administrative records and population estimates, so every county gets a figure. Covers states and counties only, because the SAHIE dataset files have no national row. The Census Bureau advises comparing years from 2008 on only; 2013 is the updated release. Working-age adults; the rate for everyone under 65 is uninsured_rate_under_65.

Every value in the ranking comes from the same publisher and the same period, so the counties are compared on one definition. Equal values share a rank.

How to cite

U.S. Census Bureau. Small Area Health Insurance Estimates (SAHIE): percent uninsured, ages 18 to 64, all races, both sexes, all income levels, states and counties. https://www2.census.gov/programs-surveys/sahie/datasets/time-series/estimates-acs/sahie-2021-csv.zip. Retrieved 2026-10-12.

Citation styles

The publisher is the author. Invokely is named only as the place the figures were read, where a style asks for it.

APA 7

U.S. Census Bureau. (2026). Small Area Health Insurance Estimates (SAHIE): percent uninsured, ages 18 to 64, all races, both sexes, all income levels, states and counties (Counties in Massachusetts by uninsured rate, ages 18 to 64 (US model-based estimate), 2021) [Data set]. Retrieved October 12, 2026, from https://www2.census.gov/programs-surveys/sahie/datasets/time-series/estimates-acs/sahie-2021-csv.zip

MLA 9

Small Area Health Insurance Estimates (SAHIE): percent uninsured, ages 18 to 64, all races, both sexes, all income levels, states and counties, Counties in Massachusetts by uninsured rate, ages 18 to 64 (US model-based estimate), 2021. U.S. Census Bureau, 6 Aug. 2026, https://www2.census.gov/programs-surveys/sahie/datasets/time-series/estimates-acs/sahie-2021-csv.zip. Invokely, https://invokely.ai/rankings/uninsured-rate-ages-18-64/massachusetts-counties?period=2021. Accessed 12 Oct. 2026.

Chicago (author-date)

U.S. Census Bureau. 2026. Small Area Health Insurance Estimates (SAHIE): percent uninsured, ages 18 to 64, all races, both sexes, all income levels, states and counties. Counties in Massachusetts by uninsured rate, ages 18 to 64 (US model-based estimate), 2021. Dataset. Accessed October 12, 2026. https://www2.census.gov/programs-surveys/sahie/datasets/time-series/estimates-acs/sahie-2021-csv.zip. Also distributed by Invokely, https://invokely.ai/rankings/uninsured-rate-ages-18-64/massachusetts-counties?period=2021.

Harvard

U.S. Census Bureau (2026) Small Area Health Insurance Estimates (SAHIE): percent uninsured, ages 18 to 64, all races, both sexes, all income levels, states and counties, Counties in Massachusetts by uninsured rate, ages 18 to 64 (US model-based estimate), 2021 [Dataset]. Available at: https://www2.census.gov/programs-surveys/sahie/datasets/time-series/estimates-acs/sahie-2021-csv.zip, via Invokely: https://invokely.ai/rankings/uninsured-rate-ages-18-64/massachusetts-counties?period=2021 (Accessed: 12 October 2026).

BibTeX
@misc{census_counties_in_massachusetts_by_2021,
  author = {{U.S. Census Bureau}},
  title = {{Small Area Health Insurance Estimates (SAHIE): percent uninsured, ages 18 to 64, all races, both sexes, all income levels, states and counties: Counties in Massachusetts by uninsured rate, ages 18 to 64 (US model-based estimate), 2021}},
  year = {2026},
  howpublished = {Data set},
  url = {https://www2.census.gov/programs-surveys/sahie/datasets/time-series/estimates-acs/sahie-2021-csv.zip},
  urldate = {2026-10-12},
  note = {Accessed via Invokely, https://invokely.ai/rankings/uninsured-rate-ages-18-64/massachusetts-counties?period=2021. Publisher attribution: U.S. Census Bureau. Small Area Health Insurance Estimates (SAHIE): percent uninsured, ages 18 to 64, all races, both sexes, all income levels, states and counties. https://www2.census.gov/programs-surveys/sahie/datasets/time-series/estimates-acs/sahie-2021-csv.zip. Retrieved 2026-10-12.},
}
RIS
TY  - DATA
AU  - U.S. Census Bureau
TI  - Small Area Health Insurance Estimates (SAHIE): percent uninsured, ages 18 to 64, all races, both sexes, all income levels, states and counties: Counties in Massachusetts by uninsured rate, ages 18 to 64 (US model-based estimate), 2021
PY  - 2026
DA  - 2026/08/06
PB  - U.S. Census Bureau
DB  - Invokely
UR  - https://www2.census.gov/programs-surveys/sahie/datasets/time-series/estimates-acs/sahie-2021-csv.zip
L2  - https://invokely.ai/rankings/uninsured-rate-ages-18-64/massachusetts-counties?period=2021
Y2  - 2026/10/12
N1  - Accessed via Invokely, https://invokely.ai/rankings/uninsured-rate-ages-18-64/massachusetts-counties?period=2021.
N1  - Publisher attribution: U.S. Census Bureau. Small Area Health Insurance Estimates (SAHIE): percent uninsured, ages 18 to 64, all races, both sexes, all income levels, states and counties. https://www2.census.gov/programs-surveys/sahie/datasets/time-series/estimates-acs/sahie-2021-csv.zip. Retrieved 2026-10-12.
ER  -
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Rank Counties in Massachusetts by uninsured rate, ages 18 to 64 (US model-based estimate) using official data, and cite the source.
rank_places {"indicator":"uninsured_rate_18_64","level":"province","within":"Massachusetts","limit":10}
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Questions

Which county has the highest uninsured rate, ages 18 to 64 (US model-based estimate)?

Nantucket County, with 4.8% in 2021, according to the U.S. Census Bureau.

Which county has the lowest uninsured rate, ages 18 to 64 (US model-based estimate)?

Norfolk County, with 2.9% in 2021.

Where does this ranking come from?

Every value comes from one source and one period, so the places are comparable: U.S. Census Bureau, Small Area Health Insurance Estimates (SAHIE): percent uninsured, ages 18 to 64, all races, both sexes, all income levels, states and counties. Retrieved 2026-10-12.

Uninsured rate, ages 18 to 64 (US model-based estimate): other rankings

Counties in Massachusetts: more rankings