The population and housing unit estimates are released on a flow basis throughout each year. Each new series of data (called vintages) incorporates the latest administrative record data, geographic boundaries, and methodology. Therefore, the entire time series of estimates beginning with the date of the most recent decennial census is revised annually, and estimates from different vintages of data may not be consistent across geography and characteristics detail.
When multiple vintages of data are available, the most recent vintage is the preferred data.

The vintage year (e.g., V2021) refers to the final year of the time series. The reference date for all estimates is July 1, unless otherwise specified.

Additional estimates files may also be accessed via the Census Bureau application programming interface (API).

Additional information on the Census Bureau's Population Estimates Program (PEP) is available on the PEP's homepage Census Bureau's Population Estimates Program.

Notes:
For vintage 2019: The estimates are based on the 2010 Census and reflect changes to the April 1, 2010 population due to the Count Question Resolution program and geographic program revisions. All geographic boundaries for the 2019 population estimates are as of January 1, 2019.

For vintage 2021: The estimates are developed from a base that incorporates the 2020 Census, Vintage 2020 estimates, and 2020 Demographic Analysis estimates. The estimates are developed from a base that incorporates the 2020 Census, Vintage 2020 estimates, and 2020 Demographic Analysis estimates.

For population estimates methodology statements, see http://www.census.gov/programs-surveys/popest/technical-documentation/methodology.html.

Sources: U.S. Census Bureau, Population Division
Annual Estimates of the Resident Population for Counties in Pennsylvania: April 1, 2010 to July 1, 2019 (CO-EST2019-ANNRES-42) - Release Date: March 2020

Annual Estimates of the Resident Population for Counties in Pennsylvania: April 1, 2020 to July 1, 2021 (CO-EST2021-POP-42) - Release Date: March 2022

The population and housing unit estimates are released on a flow basis throughout each year. Each new series of data (called vintages) incorporates the latest administrative record data, geographic boundaries, and methodology. Therefore, the entire time series of estimates beginning with the date of the most recent decennial census is revised annually, and estimates from different vintages of data may not be consistent across geography and characteristics detail.
When multiple vintages of data are available, the most recent vintage is the preferred data.

The vintage year (e.g., V2021) refers to the final year of the time series. The reference date for all estimates is July 1, unless otherwise specified.

Additional estimates files may also be accessed via the Census Bureau application programming interface (API).

Additional information on the Census Bureau's Population Estimates Program (PEP) is available on the PEP's homepage Census Bureau's Population Estimates Program.

Notes:
For vintage 2019: The estimates are based on the 2010 Census and reflect changes to the April 1, 2010 population due to the Count Question Resolution program and geographic program revisions. All geographic boundaries for the 2019 population estimates are as of January 1, 2019.

For vintage 2021: The estimates are developed from a base that incorporates the 2020 Census, Vintage 2020 estimates, and 2020 Demographic Analysis estimates. The estimates are developed from a base that incorporates the 2020 Census, Vintage 2020 estimates, and 2020 Demographic Analysis estimates.

For population estimates methodology statements, see http://www.census.gov/programs-surveys/popest/technical-documentation/methodology.html.

Sources: U.S. Census Bureau, Population Division
Annual Estimates of the Resident Population for Counties in Pennsylvania: April 1, 2010 to July 1, 2019 (CO-EST2019-ANNRES-42) - Release Date: March 2020

Annual Estimates of the Resident Population for Counties in Pennsylvania: April 1, 2020 to July 1, 2021 (CO-EST2021-POP-42) - Release Date: March 2022