There are 550 county subdivisions in Virginia known as minor civil divisions (MCDs). There are 510 districts that are used for the election of county supervisors and are known as either magisterial districts or election districts. Arlington County is not divided into districts so the entire entity is a county subdivision named Arlington. The 39 independent cities are independent of MCDs and serve as county subdivisions.
Subdivisions that are also Incorporated Places have an asterisk(*) and the link takes you to the Community Profile for the Incorporated Place.