This datalayer displays the counties for the state, based on a ground condition of January 1, 1990. The primary legal divisions of most states are termed ''counties.'' Each county and statistically equivalent entity is assigned a three-digit Federal Information Processing Standards code that is unique within the state. These codes are assigned in alphabetical order of county or county equivalent within each state. NOTE: The Census Bureau treats the portion of Yellowstone National Park in Montana as a county-equivalent for purposes of data presentation.