Just because the mailing address is "Littleton"
doesn't mean that the address is actually within the Littleton
The U.S. Post Office has designated the name "Littleton"
to stand for 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 following ZIP codes are associated with the city name, "Littleton" in Colorado: