What is Zip Code?

The term ZIP is an acronym for Zone Improvement Plan. It was chosen to suggest that the mail travels more efficiently and quickly (zipping along) when senders use the code in the postal address the basic format consists of five digits. There are no ZIP codes reserved for designating mail bound for foreign destinations (with the exception of U.S. military units stationed outside of the United States), and therefore, international outbound mail should not include a ZIP code in the delivery address.

In order to promote the idea of ZIP codes, Mr. Zip” appeared as the cartoon mascot for the campaign, touting Put ZIP in your mail!” While Mr. Zip is obviously a fictional figure, a Philadelphia postal inspector named Robert Moon is widely considered to be the real-life version and the father of the ZIP code even though the Postal Service refused to give him sole credit for the invention.

Like area codes , ZIP codes are sometimes divided and changed, especially when a rural area becomes suburban Typically, the new codes become effective once announced, and a grace period (e.g., one year) is provided in which the new and old codes are used concurrently so that postal patrons in the affected area can notify correspondents, order new stationery, etc.

Reference : USPS

Top Zip Code by Population in United States

Zip Code City State AreaCode Population Timezone
Zip Code 77449 Katy Texas 832 / 346 / 281 124,161 Central (GMT -06:00)
Zip Code 77494 Katy Texas 281 / 346 / 832 121,708 Central (GMT -06:00)
Zip Code 79936 El Paso Texas 915 118,608 Mountain (GMT -07:00)
Zip Code 77084 Houston Texas 281 / 832 / 346 109,885 Central (GMT -06:00)
Zip Code 90011 Los Angeles California 323 109,773 Pacific (GMT -08:00)
Zip Code 60629 Chicago Illinois 773 / 872 / 312 / 708 108,911 Central (GMT -06:00)
Zip Code 90650 Norwalk California 562 104,861 Pacific (GMT -08:00)
Zip Code 08701 Lakewood New Jersey 732 / 848 104,346 Eastern (GMT -05:00)
Zip Code 78521 Brownsville Texas 956 103,832 Central (GMT -06:00)
Zip Code 78572 Mission Texas 956 103,451 Central (GMT -06:00)
Zip Code 90201 Bell Gardens California 323 102,119 Pacific (GMT -08:00)
Zip Code 92335 Fontana California 909 102,029 Pacific (GMT -08:00)
Zip Code 92336 Fontana California 909 101,643 Pacific (GMT -08:00)
Zip Code 78660 Pflugerville Texas 512 101,532 Central (GMT -06:00)
Zip Code 90250 Hawthorne California 310 / 424 100,092 Pacific (GMT -08:00)
Zip Code 94565 Pittsburg California 925 98,901 Pacific (GMT -08:00)
Zip Code 77433 Cypress Texas 832 / 281 / 346 98,872 Central (GMT -06:00)
Zip Code 11226 Brooklyn New York 718 97,341 Eastern (GMT -05:00)
Zip Code 90280 South Gate California 323 97,204 Pacific (GMT -08:00)
Zip Code 90805 Long Beach California 562 / 310 96,340 Pacific (GMT -08:00)