County subdivisions are the primary divisions of counties for the
reporting of decennial census data. They include minor civil divisions
(MCDs are the primary governmental or administrative divisions of a
county such as boroughs, towns, and townships), census county divisions
(CCDs were established by the Census Bureau in 21 states where there are
no legally established MCDs), census subareas, and unorganized
territories.
Included with Maptitude and TransCAD