How many places do you know of where there is signage for one state's state route in another state? Don't count places where a highway crosses a state line and one state posts signs for its first exit on the other side of the border, since that's pretty common.
Here are some from my area:
* Exit 15 of the New York Thruway (I-87) is for I-287/NJ 17.
* There is an exit from the Delaware Expressway (I-95) in Philadelphia for the Betsy Ross Bridge (NJ 90).
* Exit 1 of I-84 in New York is for NJ 23.
Here's a link for one thread in another: https://www.aaroads.com/forum/index.php?topic=9922