From the inception of the North American Numbering Plan in 1947 through 1994, all area codes had 0 or 1 as the middle digit, and only two attempts had been made at implementing an overlay. In 1995, the first “interchangeable” area codes (with 2 through 8 as the middle digit) were introduced, beginning with 334 in Alabama and 360 in Washington state. The map above shows the area codes as they existed at the end of 1994, just before the dam burst. The pace of adding new codes peaked in 1997, with 43 new area codes in a single year. (Eight of those 43 were in the Caribbean, plus two U.S. territories in the western Pacific.)
The map is in SVG format, so it will scale smoothly to any size. If your browser doesn’t display SVG images correctly, you can view the PNG version.
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