This series of maps shows the classification of the state's 159 counties along a continuum from urban to rural.  This classification was developed by the US Department of Agriculture (by a fellow named Beale originally) and now is standardized by the US Office of Management and Budget (OMB).  It is based on urban population and commuting patterns for a county's workforce.  Thus, a rural county where a large percentage of the workforce commutes to a metro area would be classified as more urban than if its workers didn't access a more urban area regularly.