Zip codse for

The first number would represent a group of states, from zero on the east coast to nine on the west coast. The second and third numbers identified the specific mail sorting facility the letter would go to. Later, the USPS added two more numbers to track which post office handled the mail.

According to his wife, Moon was a Republican but the government was Democrat-controlled at the time. It took years and repeated attempts for his idea to be seriously considered, she said. But the grumbling eventually ceased, and the ZIPs simply became routine. The map below shows each ZIP Code's region:. After that, the ZIP Codes will proceed alphabetically.

This facility is the mail sorting and distribution center for a zone or area. Some sectional center facilities have multiple three-digit codes assigned to them. The fourth and fifth digits of the ZIP Code represent the area of the city or town. ZIP Codes are not drawn according to state boundaries. In fact, since they are designed only to increase mailing efficiency, ZIP Codes can and do cross county and state boundaries. For example:. For example ZIP Codes that start with are assigned to the Navy, and therefore have no geographic location.

In general, they are updated once every 10 years for the Census. The Census assigns an area to a ZCTA according to census blocks the smallest geographic unit used by the census. Imagine a city block that makes up a typical census block as pictured to the right. It is bounded on all 4 sides by portions of city streets that each have their own name and addresses. The issue is that census blocks almost always split down the middle of the street.

ZIP codes rarely do because that would require two postal workers delivering mail to that street - one for each side of the street. In the example, one mail carrier may deliver to 3 sides of the block via one ZIP code while another mail carrier delivers mail on the other street in a different ZIP code.

When this happens, the Census Bureau will assign the entire block to a single ZCTA in this case, because the census block is the area that is precisely measured. If you are getting very precise usually a matter of meters, not miles , census block boundaries near the edge of a ZIP code almost always split ZIP codes. The statistics provided by the Census Bureau can give insight into the demographics within the ZIP code. For instance, see our ZIP code rankings.

Remember that ZIP codes were made to make mail delivery easier. They weren't made to correspond to existing boundaries such as cities, counties, or even states.

If it is more efficient for a mail carrier to drive across a state line to deliver mail, the ZIP code "boundary" will cross the state lines. ZIP codes don't usually cross state lines, but some do , , and are good examples. The edges of the boundaries commonly overlap. For the purposes of our free zip code database by county downloads, we will commonly list either the most common region for the ZIP code or list multiple regions if several exist in the ZIP code.

For cities, the assignment is somewhat more complicated.