371 Subfield $a - Address:
Subfield $a contains all address information preceding the name of the city or town. The subfield can also contain information indicating that no address information is available. Subfield $a is repeated to indicate separations of address information.
Example:
100 1# $aSmith, Arthur
371 ## $aBox 1216$bBarrière$dCanada$eV0E 1E0