This page was for an Expedition that is now defunct. This is an archive, please do not make any further edits to this page. For the old discussion page, please see Talk:List of US Interstates.
The United States is covered with a convenient system of Interstate highways. Interstates are always freeways (limited access; no grade crossings), while U.S. Highways may be freeways on some sections and not on others. These roads network between major (and minor) population centers, and can make it easy to cover long distances – or get to the other side of a large city – quickly. Primary Interstates have one- or two-digit numbers, with odd ones running north-south (e.g. I-5) and even ones running east-west (e.g. I-80). Secondary Interstates have three digit numbers, with ones beginning with an even number (ie. 275) forming a circle or semi-circle around a city and ones beginning with an odd number forming spurs into a city (ie.175).
This is a list of primary interstates of the US Interstate Highway System.