Wouldn't you think an interstate highway would have to serve at least two states? Well, there are 14 major highways that don't leave the state they start in.
Only trunk interstates, no spurs, loops, or bypasses.
Alaskan, Hawaiian and Puerto Rican interstates don't count.
I-86 and I-88 aren't listed here because there are multiple interstates with those numbers.
Similarly, I-11 is currently only in Nevada, but it will cross into Arizona in the future.