Population measures provide insight on the changing size and face of communities. The racial and ethnic composition of a community can offer insight into its levels of diversity, which can bring with it challenges and opportunities.

MetroWest has grown more diverse since 2000. Its Asian population grew fastest, gaining 118%, while the African American population increased 95%, and Hispanic residents grew 101%. The white population was largely stable and still makes up a large majority, with 2,423,500 residents. The white majority has fallen from 88% of the population in 2000 to 76% in 2016-20.

Massachusetts experienced similar changes, but compared to MetroWest, it had smaller increases in its Asian, African American, and Hispanic populations (96%, 49% and 93%, respectively). Racial and ethnic minority populations also increased at the national level, but at a slower pace than either MetroWest or Massachusetts.

White residents were the largest racial group in every municipality in MetroWest in 2016-20, but some localities experienced large increases in other racial groups since 2000. The areas with the largest Asian population were Lexington, at 30%, and Acton and Westford, both at 23%. Westborough, Bedford and Boxborough follow, with 22%, 17%, and 16% of their populations being Asian, respectively. Dedham has the largest percentage of African Americans, at 8% of its population. Overall, Framingham, at 17%, has the highest percentage of Hispanic residents, followed by Waltham and Marlborough at 14% and 13%, respectively.

The composition of the U.S. population is becoming more racially and ethnically diverse as people of color grow in representation and will be a majority within the next two decades. Latino, Asian and multiracial groups are experiencing the largest growth with Latino's rapid increase caused largely by immigration. Latino immigrants who enter the U.S. tend to be younger and of child-bearing age. Latinas in the U.S. have higher fertility rates than Black and white women. Black, Latino and multiracial populations are also experiencing higher rates of births relative to deaths, while whites are experiencing the opposite.

Rate is percentage change from 2000. The multiyear figures are from the Census Bureau's American Community Survey. The bureau combined 5 years of responses to the survey to provide estimates for smaller geographic areas and increase the precision of its estimates. However, because the information came from a survey, the samples responding to the survey were not always large enough to produce reliable results, especially in small geographic areas. CGR has noted on data tables the estimates with relatively large margins of error. Estimates with three asterisks have the largest margins, plus or minus 50% or more of the estimate. Two asterisks mean plus or minus 35%-50%, and one asterisk means plus or minus 20%-35%. For all estimates, the confidence level is 90%, meaning there is 90% probability the true value (if the whole population were surveyed) would be within the margin of error (or confidence interval). The survey provides data on characteristics of the population that used to be collected only during the decennial census.

The Census Bureau asks people to identify their race (white, African-American, etc.) separate from their ethnicity (Hispanic or non-Hispanic). So the totals for these categories cannot be added together, as people show up in both a racial and ethnic group. Data for this indicator are released annually in December.