This is the Colorado ZIP code website, which contains 664 ZIP codes, 426 cities, 64 counties, and more than 615,818 ZIP+4 codes. Each 9-digit ZIP code corresponds to one or several Colorado addresses.
Besides, there are also some tools related to ZIP code or address. For example, address verification, full ZIP code search, random address generator, etc.

State-image: co

Cities in Colorado


Please check ZIP Codes by City Name:

Counties in Colorado


How to write a U.S. envelope?

  • First, you need to fill in the recipient's mailing information in the center of the envelope. The first line is the recipient's name, the second line is the street address with a detailed house number, and the last line is the city, state abbr, and ZIP Code.

    Second, write the sender's information on the left top corner of the envelope. If your mail cannot be delivered, it will return to the sender's address.

    Finally, don't forget to stick the stamp on the right top corner. Otherwise, the letter will not go into the delivery process.

    Here is the envelope example below.

    ZIP Code: homepage
  • United States Envelope Example

For more explanation, please read the official document: USA.pdf (English)



The population of the state Colorado was 5,029,196 in 2010 and reached 5,758,736 in 2019 with an increase of +729,540. Now the state Colorado is the 21th state by population size in the U.S. and accounts for 1.74% of the total U.S. population.

Area2019 Census Data2010 Census DataIncreaseIncrease(%)RankProportion of total population(%)