ZIP Codes are a system of postal codes used by the USPS(United States Postal Service). It is introduced in 1963. The basic format consists of five numerical digits includes ZIP Code, a hyphen, and four additional digits.
The first digit of the ZIP Code is allocated as follows:
- 0 = Massachusetts (MA), Connecticut (CT), Maine (ME), New Hampshire (NH), New York (NY, Fishers Island only), New Jersey (NJ), Vermont (VT), Puerto Rico (PR), Rhode Island (RI), Virgin Islands (VI), Army Post Office Europe (AE), Fleet Post Office Europe (AE)
- 1 = New York (NY), Delaware (DE), Pennsylvania (PA)
- 2 = District of Columbia (DC), South Carolina (SC), Maryland (MD), North Carolina (NC), Virginia (VA), West Virginia (WV)
- 3 = Alabama (AL), Georgia (GA), Florida (FL), Mississippi (MS), Army Post Office Americas (AA), Tennessee (TN), Fleet Post Office Americas (AA)
- 4 = Indiana (IN), Michigan (MI), Kentucky (KY), Ohio (OH)
- 5 = Iowa (IA), South Dakota (SD), Minnesota (MN), North Dakota (ND), Montana (MT), Wisconsin (WI)
- 6 = Kansas (KS), Missouri (MO), Illinois (IL), Nebraska (NE)
- 7 = Louisiana (LA), Oklahoma (OK), Arkansas (AR), Texas (TX)
- 8 = Arizona (AZ), Idaho (ID), New Mexico (NM), Colorado (CO), Nevada (NV), Utah (UT), Wyoming (WY)
- 9 = Alaska (AK), California (CA), American Samoa (AS), Guam (GU), Federated States of Micronesia (FM), Hawaii (HI), Marshall Islands (MH), Northern Mariana Islands (MP), Washington (WA), Oregon (OR), Palau (PW), Army Post Office Pacific (AP), Fleet Post Office Pacific (AP)