Post Office Changes   Old/New Finance No. ZIP Code State P.O. Name County/Parish Station/Branch/Unit Unit Type Effective Date Comments Old 23-0378 21234 MD Baltimore Baltimore Parkville Classified Branch   New 23-0378 21286 MD Baltimore Baltimore Loch Raven Classified Branch 07/01/2017 Realign ZIP Code™ boundaries. Use Loch Raven, MD 21286 as last line of address for the 872 deliveries previously in ZIP Code 21234. — Address Management, Product Information, 6-22-17