<font face="Verdana, Arial, Helvetica, sans-serif" size="2">Originally posted by Doppy:
The Farley Post Office in NYC is always open. It's on 33rd & 8th, across from Penn Station and MSG. The new Penn Station is actually kicking the PO out of most of that building.
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While they're open on sundays for window service/express mail service, I don't believe that regular or priority mail deposited is posmarked until moday.