Just because the mailing address is "Littleton" doesn't mean that the address is actually within the Littleton city limits.
The U.S. Post Office (USPS) has designated the name "Littleton" to include several local communities, both incorporated and unincorporated areas of three counties. ZIP Codes can represent an area within a state (an area that may or may not cross county boundaries), an area that crosses state boundaries (an unusual condition), or a single building or company that has a very high mail volume.
The USPS has used the following ZIP Codes with the city name "Littleton" in Colorado:
|ZIP code||Area within city limits
||County||Other city names used by the USPS||Type of ZIP code|
|80120||Completely within the
Littleton city limits
|80121||Partially within the Littleton city limits||Arapahoe||Greenwood Village, Centennial||Standard|
|Bow Mar, Columbine Valley, Denver, Lakewood||Standard|
|80163||Yes||Douglas||Highlands Ranch||P.O. Boxes|