There are two sets of rules to comply with when moving a mailbox: guidelines of the U.S. Postal Service and most local governments. Although there are differences from jurisdiction to jurisdiction, there are common rules regarding moving a mailbox.
Postal Service Rules
The Postal Service permits moving a mailbox, but it must be placed in a location that is readily accessible by a mail carrier. For example, roadside mailboxes must in a location where mail carriers can place mail from their delivery vehicles.
Roads Without Curbs
A typical local rule requires a mailbox to be offset the entire width of a shoulder off the road with an addition of a specific number of inches.
On any street with a curb, a mailbox must be relocated a specified number of inches from the face of the curbside. The typical space is 10 inches or a bit less.
Before relocating a mailbox, you should call both the post office and city hall for the applicable rules before moving a mailbox.
Improperly relocating a mailbox can result in a postal patron's mail delivery being suspended.