There are 254 counties in Texas. All counties are functioning governmental units, each governed by a Commissioners Court.
There are 862 county subdivisions in Texas. They are all census county divisions (CCDs), which are delineated for statistical purposes, have no legal function, and are not governmental units.
Texas Counties - Populated Places in 254 Counties
Also see County: Census Data | Physical, Cultural & Historical Features | ZIP Codes | Land, Farms, & Ranches