List of Interstate Highways
Primary Interstate Highways are the major interstate highways of the United States and have a one or two-digit route number.  Even (0, 2, 4, 6, or 8) route numbers are given to east/west routes, with the smaller numbered routes in the  south (I-10) and bigger numbered routes in the north (I-90).  Similarly, odd (1, 3, 5, 7, or 9) route numbers are given to north/south routes, with the smaller numbered routes in the west (I-5) and the bigger numbered routes in the east (I-95). Routes that end in a 0 or a 5 are major routes in the system. These Interstates generally go from coast to coast or from the bottom to the top of the U.S. For example, Interstate 5 goes from the Mexican Border at San Diego, California to the Canadian Border at Blaine, Washington. Likewise, Interstate 10, the southernmost cross-country Interstate Highway, goes from Santa Monica, California on the west coast to Jacksonville, Florida on the east coast. The longest Interstate Highway in the United States is Interstate 90.