Census Data for Chester County

Most of the data sests listed below are generated by the US Census Bureau. If you have any questions about the data, please contact CCPC's Senior Demographer at 610-344-6285 or ccplanningObfuscation@chesco.org.

In the past, the US Census Bureau used to gather all its data every ten years as part of what is formally called the "Decennial Census." In recent decades, however, the Bureau has expanded their data gathering operations. They currently posts three major types of data at their web site. These three data types are:

1. The Decennial Census, which counts (or "enumerates") the population once every ten years. The last Decennial Census enumeration was in 2020.
2. The American Community Survey, which generates US population data each year based on surveys that are mailed out monthly on an ongoing basis to a random sample of households through the US.
3. Population and Housing Unit Estimates, which estimate the US population each year by examining records documenting births, deaths, immigration, and outmigration.

Another excellent source for census data relating specifically to Pennsylvania is the Pennsylvania State Data Center. Data focusing on Philadelphia and its suburbs are also available from the "Data Catalog" posted on the Delaware Valley Regional Planning Commission's website.

The Decennial Census for Chester County

On May 25, 2023, the U. S. Census Bureau released new local level data from the 2020 Census that is more detailed than the available data that was released in 2021. This expanded data release contains detailed information on age, sex, families, households, and housing. From this data set, Planning Commission staff extracted the data relating to Chester County's 73 municipalities and formatted it in an easy-to-use Excel format.

The Census Bureau has created a web page entitled Infographics and Visualizations which includes maps and charts illustrating the 2020 census results. One of these maps is the 2020 Census Demographic Data Map Viewer, which provides selected data about counties and census block groups nationwide. Another useful map provides 2020 State and County population and housing data.

2010 Decennial Census data can be downloaded from the links below:

• Pennsylvania: 2010 Population and Housing Unit Counts 2010 Census of Population and Housing
• Pennsylvania: 2010 Summary Population and Housing Characteristics 2010 Census of Population and Housing

Decennial Census data from 1790-2000 are available by contacting CCPC's Senior Demographer at 610-344-6285 or ccplanningObfuscation@chesco.org.

The American Community Survey (ACS): 1-Year and 5-Year Survey Data

Download a pdf of this
Guide to the ACS.

Every year, the Census Bureau sends out over 3 million surveys which include more detailed questions then are asked on the decennial Census. These surveys are mailed out as part of the American Community Survey (ACS).

The ACS compiles the yearly survey results to generate estimated data of the current population, and other demographic features.

ACS "estimated data" is not "enumerated" or counted. Rather they are statistically estimated, and presented in two ways:

1. ACS 1-Year Survey Data

Each year, the ACS produces 1-year estimated data annually for geographic areas with a population of 65,000 or more. This includes the nation, all states, all congressional districts, approximately 800 counties, and many metropolitan areas. These 1-year ACS estimated data are not generated for most of the municipalities in Chester County.

2. 5-Year ACS Survey Data

The ACS produces 5-year estimated data annually for geographic areas with large and small populations, including the 73 municipalities in Chester County. These 5-year estimated data represent a compilation of data gathered over a five year period. Thus, the 2010 5-year estimated data were based in ACS data collected from 2005 through 2009. Note that the 5-year estimated data are not simply averages of the 1-year estimates.

Population Estimates

Each year the US Census Bureau generates "Population Estimates" through its Population Estimates Program (PEP). These estimates are generated each year by using the enumerated Decennial Census data as a base data set, and then adding annual data on births and immigration while subtracting annual data on deaths and out-migration. Information on the PEP methodology can be found online. The PEP program also generates "Housing Estimates." The PEP posts their data sets online.