St. Clair County Population - Illinois

Data Item State County
Population, 2019 estimate - (Number)
Year Value
2000256,208
2001255,922
2002257,123
2003257,753
2004258,406
2005258,849
2006260,503
2007261,238
2008262,131
2009263,617
2010270,353
2011270,048
2012268,673
2013266,831
2014265,941
2015264,858
2016263,187
2017262,600
2018261,360
2019259,686

Sources: U.S. Census Bureau, Population Estimates Program (PEP), updated annually. Population and Housing Unit Estimates

Definitions:

The Census Bureau's Population Estimates Program (PEP) produces estimates of the population for the United States, its states, counties, cities, and towns, as well as for the Commonwealth of Puerto Rico and its municipios (county-equivalents for Puerto Rico). Additionally, housing unit estimates are produced for the nation, states, and counties. The timing of the release of estimates varies according to the level of geography. See the Schedule of Releases for more information.

Resident Population - All persons who are "usually resident" in a specified geographic area. For the United States, the resident population includes all persons who usually reside in the 50 states and the District of Columbia, but excludes residents of the Commonwealth of Puerto Rico and the Island areas under U.S. sovereignty or jurisdiction (principally American Samoa, Guam, United States Virgin Islands, and the Commonwealth of the Northern Mariana Islands). In addition, the U.S. resident population excludes U.S. Armed Forces overseas and civilian U.S. citizens whose usual place of residence is outside the United States.

Estimates Base - The population count or estimate used as the starting point in the estimates process. It can be the most recent updated Census count or the estimate for a previous date within the same vintage. (The vintage year (e.g., V2019) refers to the final year of the time series). The April 1, 2010 Population Estimates base reflects changes to the 2010 Census population from the Boundary and Annexation Survey (BAS) and other geographic program revisions. It may reflect changes from the Count Question Resolution program. Click on the "Scope and Methodology" link for details for each vintage year.

Population percent change - The difference between the population of an area at the beginning and end of a time period, expressed as a percentage of the beginning population.

Methodology for U.S. and Puerto Rico