The city of Earth City is assigned specific ZIP Code(s) by the United States Postal Service (USPS) to make mail delivery accurate and efficient. A ZIP Code in Earth City helps identify the correct postal area, ensuring that letters, parcels, and packages reach the right neighborhood or post office without delay. For residents, businesses, and visitors, knowing the correct Earth City ZIP Code is important not only for mailing purposes but also for location-based services, navigation, and demographic reference.
| Post Office | Earth City |
| County | Saint Louis |
| State | Missouri |
| ZIP Code | 63045 |