Population measures provide insight on how communities are changing in size and composition. The racial and ethnic makeup of a community can offer insight into its levels of diversity, which also may reflect particular challenges and opportunities.

From 2009-13 to 2019-23, Lancaster County's Hispanic population grew the fastest, at 33%, followed by the Asian population at 27%. Its African American population increased by 13% and its white population declined by 2%. Despite these shifts, the white population still makes up a large majority, with about 460,000 residents.

The growth in Lancaster County's Hispanic population from 2019-23 outpaced the nation but was lower than the state. Lancaster had the second smallest growth rate among Hispanics compared to surrounding counties and was similar to Chester at 32%. The growth in Lancaster County's African American population was similar to York (14%) and lower than Lebanon (23%). Cumberland had the largest increase in its African American population (53%) and Chester was the only county to experience a decrease in its African American population.

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 2009-13. 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.