[3] In 1814, the Treaty of Fort Jackson opened the territory to American settlers, which in turn led to a more rapid rate of county creation.

By 1830 there were 36 and Native Americans still occupied large areas of land in northeast and far western Alabama.

The first three prefixes are reserved for the state's historically most populous counties, and thereafter proceed alphabetically.

[10] The Federal Information Processing Standard (FIPS) code, used by the United States government to uniquely identify counties, is provided with each entry.

The FIPS code links in the table point to U.S. Census "quick facts" pages for each county.