what are the digits that follow the zip code
3 Digit Zip Code Map. You can easily create a 3 Digit Zip Code map using Mapline. The 1st digit of a five-digit ZIP Code represents the division of the USA into 10 large groups of states numbered from 0 (Northeast) to 9 (West). The 2nd and 3rd digits represent the states that are divided into even 10 smaller geographical areas. Also known as âsec center,â they are useful in processing and sorting mails. The US Zip Codes were assigned using the following criteria: Those starting with â0â were assigned to MA, RI, NH.