California
Oregon
Washington (PART 1/PART 2)
In addition to being the only interstate to touch both the Canadian and Mexican borders, Interstate 5 is also part of the Pan-American Highway, a 17,000-mile (26,000 km) road that runs from Alaska to Chile.
If you're interested in 3di's I-105 is the lowest number.
I-5W was a route that led into the San Francisco Bay Area. Its route is now incorporated by I-505 and I-580. What is now I-5 would've been I-5E.