Following the Louisiana Purchase and the admittance of Louisiana into the United States in 1812, five counties were formed out of the Missouri Territory at the first general assembly: Cape Girardeau, New Madrid, Saint Charles, Saint Louis, and Ste.

Its primary responsibilities include maintaining roads, providing security, prosecuting criminals, and collecting taxes.

Elected officials at this level include a sheriff, prosecuting attorney, and assessor.

[5][6] The Federal Information Processing Standard (FIPS) is used by the U.S. government to uniquely identify counties, and is provided for each entry.

These codes link to the United States Census Bureau's "quick facts" for each county.