What is the name and length of the U.S. postal code?

In the United States, it is known as a ZIP Code. It is five digits long, though it is frequently expanded to nine digits (the ZIP+4 code) for higher delivery accuracy.

What is the postal code for Washington, D.C.?

Washington, D.C. uses many codes starting with 200–205; for example, the White House uses 20500 and the Georgetown area uses 20007.

What is a ZIP+4 code?

A ZIP+4 code uses a hyphen and four additional digits after the standard five-digit ZIP Code to identify a specific delivery route, such as a side of a street, a specific building, or a floor.

How can I find a specific ZIP code in United States?

You can use the Postindex.net search bar or browse our regional directory of United States to find accurate ZIP codes for any city or street.

United States Zip Codes — Full List of Regions

United States Statistic

Capital

Washington, D.C.

ISO Alpha-2

ISO Alpha-3

USA

Calling code

Currency

US Dollar ($)

Code Format

NNNNN-NNNN

Regions / States

3,287

Total Postcodes

40,865

About United States Postal System

The United States Postal Service (USPS) administers one of the most complex and high-volume delivery networks in the world, processing billions of mail pieces annually. Established in 1963, the Zone Improvement Plan (ZIP) utilizes a hierarchical numeric system to streamline routing across 50 states and various territories. This system is foundational to American logistics, e-commerce, and geographic data analysis.

Address Example in United States

MS. MARY REED
1600 PENNSYLVANIA AVE NW
WASHINGTON DC 20500-0003
USA

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Code Structure

The ZIP Code is a five-digit numeric code. The first digit represents a group of states, the second and third digits represent a central post office facility (SCF), and the last two digits represent a small post office or local delivery area. The optional +4 extension identifies a specific delivery segment.

FAQ about United States

Popular Zip Codes

Code	Locality	Region
90001	Los Angeles	Los Angeles
90002	Los Angeles	Los Angeles
94203	Sacramento	Sacramento
94204	Sacramento	Sacramento
20001	Washington	Washington
20002	Washington	Washington
33101	Miami	Miami
33102	Miami	Miami
30301	Atlanta	Atlanta
30302	Atlanta	Atlanta
10001	New York City	New York City
10002	New York City	New York City