From: Ron Newman (

Just for the hell of it, I decided to make a list of all known places where the US Interstate Highway System's numbering system for 2-digit routes is violated.

The 2-digit numbering system is based on the principle that:

This standard is violated for a number of perfectly good reasons:

When you think about it, it's actually surprising how _few_ times the standard is violated.

Anyway, here's the list, as taken from my 1993 AAA Road Atlas. Additions and corrections are welcome.

East-West Interstates:

North-South Interstates:

Go to the list of 2 digit Interstates