Area Code Guides
In-depth reference articles about North American area codes — history, geography, how splits and overlays work, and more.
Eastern Time Zone Area Codes: A Complete Guide
The Eastern Time Zone is home to more area codes than any other in North America. Here's a comprehensive guide to every state and territory in the Eastern zone and their codes.
Area Code 213: Los Angeles and the Birth of California's Phone System
Area code 213 once covered all of California. Today it covers a small slice of downtown Los Angeles. The story of 213's dramatic shrinkage mirrors California's explosive growth.
Why Washington State Has Six Area Codes
Washington started with a single area code in 1947. Today it has six. Here's how 509, 206, 253, 360, 425, and 564 divide up the Evergreen State.
Area Code 202: Washington D.C.'s Number Since 1947
Area code 202 has served the US capital since the North American Numbering Plan was created. It's one of the few original 1947 codes still covering its original territory.
How to Identify Where a Phone Call Is Coming From
Getting a call from an unknown number? The area code is your first clue. Here's how to quickly look up where any call originates — and what the area code can and can't tell you.
Area Code Splits vs. Overlays: What's the Difference?
When an area code runs out of numbers, regulators can either split the territory or add an overlay. Both approaches have trade-offs. Here's a clear explanation of each.
The 1990s Area Code Explosion: How America Ran Out of Numbers
Between 1995 and 2000, the US added more area codes than it had in the previous 45 years combined. The culprit? Cell phones, fax machines, pagers, and the internet.
Area Code 808: Hawaii's Single Area Code Explained
The entire Hawaiian island chain — from Kauai to the Big Island — is served by a single area code. Here's the story of 808 and why the islands have never needed a second one.
Area Code 907: Why Alaska Has Just One Area Code
Alaska is the largest US state by area but has only one area code. How has 907 managed to serve a state larger than Texas, California, and Montana combined?
What Is an Overlay Area Code?
Overlay area codes let two or more area codes serve the same geographic territory. They're controversial but now widespread. Here's exactly how they work.
Area Code 212: The Story Behind New York's Original Number
Area code 212 is one of the most recognized phone numbers in the world. Here's the full history of New York City's original area code and how it has changed over the decades.
The North American Numbering Plan: How Area Codes Work
Every phone number in the US, Canada, and 18 other countries follows the same plan. Here's how the North American Numbering Plan came to be and why it still matters.