United States Zip Code Overview

ZIP codes are a system of postal codes used by the United States Postal Service (USPS) since 1963. Before 1963, cities simply had postal zones” in 124 of the nation's most populated areas But when mail started to boom, in order to meet the growing demand, the U.S. Postal Service decided to add five numbers to addresses to make mail more efficient as a part of a Zone Improvement Plan (the ZIP in ZIP code stands for Zone Improvement Plan). ZIP codes are used by the US Postal Service to map the most efficient routes for mail carriers to follow.

ZIP Codes are numbered with the first digit representing a certain group of U.S. states, the second and third digits together representing a region in that group (or perhaps a large city) and the fourth and fifth digits representing a group of delivery addresses within that region. The fourth and fifth digits were proposed by Henry Bentley Hahn Sir which gives a more precise locale within the SCF 6 The SCF sorts mail to all post offices with those first three digits in their ZIP Codes. Robert Moon is considered the father of the ZIP Code. He submitted his proposal in 1944 while working as a postal inspector 5 The post office only credits Moon with the first three digits of the ZIP Code, which describe the sectional center facility (SCF) or "sec center." An SCF is a central mail processing facility with those three digits.

Reference : WikiPedia
united states state wise zip code details

Top States by Population in United States

StateZip CodesCitiesPopulationTimezones
California2,5871,23737,253,956Pacific (GMT -08:00)
Texas2,5941,46725,145,561Central (GMT -06:00) Mountain (GMT -07:00)
New york2,1491,60819,378,102Eastern (GMT -05:00)
Florida1,47052718,801,310Eastern (GMT -05:00) Central (GMT -06:00)
Illinois1,5681,27812,830,632Central (GMT -06:00)
Pennsylvania2,1731,78512,702,379Eastern (GMT -05:00)
Ohio1,4151,06311,536,504Eastern (GMT -05:00)
Michigan1,1588799,883,640Central (GMT -06:00) Eastern (GMT -05:00)
Georgia9516299,687,653Eastern (GMT -05:00)
North carolina1,0797579,535,483Eastern (GMT -05:00)

Top Cities by Population in United States

CityStateZip CodesPopulationTimezones
New yorkNew York1458,175,133Eastern (GMT -05:00)
Los angelesCalifornia973,792,621Pacific (GMT -08:00)
ChicagoIllinois902,695,598Central (GMT -06:00)
HoustonTexas1782,099,451Central (GMT -06:00)
PhiladelphiaPennsylvania871,526,006Eastern (GMT -05:00)
PhoenixArizona751,445,632Mountain (GMT -07:00)
San antonioTexas851,327,407Central (GMT -06:00)
San diegoCalifornia801,307,402Pacific (GMT -08:00)
DallasTexas1051,197,816Central (GMT -06:00)
San joseCalifornia59945,942Pacific (GMT -08:00)

Top Zip Code by Population in United States

Zip CodeCityStateAreaCodePopulationTimezone
Zip Code 77449KatyTexas832 / 346 / 281124,161Central (GMT -06:00)
Zip Code 77494KatyTexas281 / 346 / 832121,708Central (GMT -06:00)
Zip Code 79936El PasoTexas915118,608Mountain (GMT -07:00)
Zip Code 77084HoustonTexas281 / 832 / 346109,885Central (GMT -06:00)
Zip Code 90011Los AngelesCalifornia323109,773Pacific (GMT -08:00)
Zip Code 60629ChicagoIllinois773 / 872 / 312 / 708108,911Central (GMT -06:00)
Zip Code 90650NorwalkCalifornia562104,861Pacific (GMT -08:00)
Zip Code 08701LakewoodNew Jersey732 / 848104,346Eastern (GMT -05:00)
Zip Code 78521BrownsvilleTexas956103,832Central (GMT -06:00)
Zip Code 78572MissionTexas956103,451Central (GMT -06:00)
Zip Code 90201Bell GardensCalifornia323102,119Pacific (GMT -08:00)
Zip Code 92335FontanaCalifornia909102,029Pacific (GMT -08:00)
Zip Code 92336FontanaCalifornia909101,643Pacific (GMT -08:00)
Zip Code 78660PflugervilleTexas512101,532Central (GMT -06:00)
Zip Code 90250HawthorneCalifornia310 / 424100,092Pacific (GMT -08:00)
Zip Code 94565PittsburgCalifornia92598,901Pacific (GMT -08:00)
Zip Code 77433CypressTexas832 / 281 / 34698,872Central (GMT -06:00)
Zip Code 11226BrooklynNew York71897,341Eastern (GMT -05:00)
Zip Code 90280South GateCalifornia32397,204Pacific (GMT -08:00)
Zip Code 90805Long BeachCalifornia562 / 31096,340Pacific (GMT -08:00)