Many areas with population centers have many zip codes for the same city or large town.
But in Houlton Maine and Aroostook County zip codes mean something different.
For example, Houlton's 04730 zip covers all of Houlton that is six miles by six miles in size geographically. AND you get parts of the town of Littleton...to the north. Some of the northern section of Littleton Maine spills into 04760 which is the post office jurisdiction of Monticello Maine. To the west of Houlton you get Hammond, Ludlow, to the south into Hodgdon, Linneus, etc.
So when someone says you are looking for a home on such and such an address with the Houlton Maine 04730 zip, don't assume it is actually in Houlton.
For years everything from RFD 1 and up which at least helped the reader know oh...that is out the County Road or north on US Rt 1. But 911 even though it has a precise system behind it , it did away with a system that was effective and locally well understood by the folks that lived here. 04763 covers Oakfield Maine but again not just Oakfield. So it goes zip code wise in Aroostook, Northern Penobscot and Northern Washington Counties.For help with zip codes, visit here.