The Washington/Baltimore air systems planning region stretches from Harford County , Maryland , on the Susquehanna River to the north to Spotsylvania County , Virginia , in the south, and from the Chesapeake Bay in the east to the foothills of the Appalachian Mountains in the west. This air systems planning region consists of 25 jurisdictions, 161 Aviation Analysis Zones, and 2,604 Transportation Analysis Zones.
Aviation Analysis Zone System
