ZIP Code Lookup Guide: How to Find Cities & States by Address

The US Postal Code System

ZIP Codes (Zone Improvement Plan) were introduced by the USPS to improve mail delivery speeds. Our ZIP Code lookup guide details how these numeric identifiers map addresses globally.

ZIP Code Structure:

The 5 digits represent a specific geographic area:

• First Digit: Represents a group of US states (e.g. 9 for the West Coast).
• Next Two Digits: Represents a sectional center facility (SCF) mail hub.
• Final Two Digits: Represents a local post office delivery area.

Resolve city, state, and coordinates instantly using our ZIP Code Lookup tool.