About US ZIP Codes
The ZIP Code system, also known as the Zone Improvement Plan Code, is a postal code system used in the United States to help facilitate the efficient delivery of mail. This system was introduced in 1963 and has been a crucial component of the United States Postal Service ever since. The ZIP Code system is comprised of five-digit codes, with an optional four-digit extension that can further refine the location of the address. The first three digits of the ZIP Code represent a sectional center facility (SCF) that serves a particular geographic region. The fourth and fifth digits represent smaller post offices or delivery zones within the SCF area. The ZIP Code system was developed in response to the growing volume of mail being sent and delivered throughout the United States. Prior to the introduction of the ZIP Code system, mail was sorted and delivered using a combination of city, state, and street address information. This process was often slow and inefficient, resulting in delays and lost mail. With the introduction of the ZIP Code system, mail could be sorted and delivered more quickly and accurately. The use of ZIP Codes also made it easier to track and monitor mail delivery, which helped to reduce lost or delayed mail.
ZIP Code Geography
There are several types of US ZIP Codes:
- Standard - This type generally covers a specific delivery area and are represented as polygons on our maps.
- Post Office (PO) Box - Usually represented as point at the location where the Post Office boxes are located but some are represented by a polygon on our maps.
- Unique - This type is usually a high volume mail location such as an office building or government building. These are usually represented with a point on our maps.
- Military - This type has no fixed location so they are not available on our maps.
Standard (also known as non-unique) ZIP codes usually do not cross state lines but they do cross city and county lines. There are a couple exceptions to the state line rule: One example is ZIP code 42223 which is shared between Kentucky and Tennessee. For ZIP Codes within a US State we provide data on all counties, cities, neighborhoods and school districts within it's area. For certain areas where we currently have data we also provide school attendance area information.
Level 1 ZIP Code Zones
The US ZIP Code system is divided into 10 zone which represent the first digit in each ZIP Code (0 to 9). These zones are regionally based with 0 in the Northeast increasing westward with 9 in the Western US and pacific.
Level 2 ZIP Code Zones
At the 2 digit level ZIP Codes can be further refined geographically.
State Level ZIP Code Maps:
- Alabama ZIP Code Map
- Alaska ZIP Code Map
- American Samoa ZIP Code Map
- Arizona ZIP Code Map
- Arkansas ZIP Code Map
- California ZIP Code Map
- Colorado ZIP Code Map
- Connecticut ZIP Code Map
- Delaware ZIP Code Map
- Washington DC ZIP Code Map
- Florida ZIP Code Map
- Georgia ZIP Code Map
- Guam ZIP Code Map
- Hawaii ZIP Code Map
- Idaho ZIP Code Map
- Illinois ZIP Code Map
- Indiana ZIP Code Map
- Iowa ZIP Code Map
- Kansas ZIP Code Map
- Kentucky ZIP Code Map
- Louisiana ZIP Code Map
- Maine ZIP Code Map
- Maryland ZIP Code Map
- Massachusetts ZIP Code Map
- Michigan ZIP Code Map
- Minnesota ZIP Code Map
- Mississippi ZIP Code Map
- Missouri ZIP Code Map
- Montana ZIP Code Map
- Nebraska ZIP Code Map
- Nevada ZIP Code Map
- New Hampshire ZIP Code Map
- New Jersey ZIP Code Map
- New Mexico ZIP Code Map
- New York ZIP Code Map
- North Carolina ZIP Code Map
- North Dakota ZIP Code Map
- Ohio ZIP Code Map
- Oklahoma ZIP Code Map
- Oregon ZIP Code Map
- Pennsylvania ZIP Code Map
- Puerto Rico ZIP Code Map
- Rhode Island ZIP Code Map
- South Carolina ZIP Code Map
- South Dakota ZIP Code Map
- Tennessee ZIP Code Map
- Texas ZIP Code Map
- Utah ZIP Code Map
- Vermont ZIP Code Map
- Virgin Islands ZIP Code Map
- Virginia ZIP Code Map
- Washington ZIP Code Map
- West Virginia ZIP Code Map
- Wisconsin ZIP Code Map
- Wyoming ZIP Code Map