Population data are required in nearly every area of planning and analysis by private and public agencies. Such data are essential for calculating birth and death rates, physicians-to-population ratios, hospital discharge rates, life tables, etc.

The Missouri Department of Health and Senior Services maintains population files for Missouri and its 115 counties (114 counties plus the City of St. Louis, which is an independent city) by sex for selected age groups. In addition, race detail for the state, Kansas City, and the ten counties with the largest minority populations is available. The ten counties for which race detail is provided include: Boone County, Greene County, Jackson County, Mississippi County, New Madrid County, Pemiscot County, Scott County, St. Charles County, St. Louis County, and St. Louis City. Population estimates at the state level for Hispanics or Latinos are also provided.

For decennial Census years (i.e., 1990, 2000, 2010, etc.) the April 1 Census counts are used. All other years use a July 1 mid-year point as their date of reference. Estimates for the decade of the 1990s were produced by the Department of Health and Senior Services (DHSS) after the 2000 Census was released. The 1991-1999 age distributions were based on the 1990 and 2000 endpoints. The US Census Bureau provided controls for population at the county and state levels. Population for 2001 and later years comes from the US Census Bureau in partnership with the Federal State Cooperative Program for Population Estimates.

Three other related notes: for 1990 the Modified-Age-Race-Sex (MARS) population numbers are used. For 2000, we have added in the population from a prison in DeKalb County that was erroneously missed in the 2000 Census. The under 1 population count for all years and geographies comes from resident live births in Missouri using the Missouri Vital Records system.

The race estimates for the ten counties, Kansas City, and the state are compatible with previous 1990s era estimates in that each person in a county is assigned to one of three race groups (white, black, or other). The race estimates were derived from bridged estimates produced by the National Center for Health Statistics from Census 2000. For 2000 and later years, numbers were taken directly from NCHS while the 1990s era age distributions were developed by DHSS using Census controls.

Population files by ZIP code and other Census geographies (e.g., census tract) are also maintained by DHSS staff. These files are usually limited to decennial Census years.

DHSS staff also manage an assortment of other files with demographic indicators. A limited number of files pertaining to population projections are available. DHSS uses numbers developed by the Missouri Division of Budget and Planning for county- and state-level projections. Intermittently, DHSS produces population projections by ZIP code for a limited number of years and age groups.

Most of the population data can be accessed through the Population MICA, which can be found on the DHSS website. Charges for development of other population estimates and projections follow the data fee policy.