I served in the USS Piedmont (AD-17), a Destroyer Tender.
AD's were named after geographical regions of the US. The PIEDMONT was a Dixie class tender. There were three AD's operating within out of San Diego during my era. The DIXIE, PRAIRIE, and PIEDMONT. Each took a rotation 6 month WESTPAC cruise, followed by 9 months in our homeport.
A late 60's built AD, the SAMUEL GOMPERS, was I believe the first AD to bear a name of an individual vs. a geographical area.
My former "home"...