Yeah what is with "Philadelphia" being signed on US 40? Also the fact that MD 7 is called Philadelphia Road leading out of Baltimore.
Also to note on US 301, the Wilmington had to be added on sometime in the late 80's or early 90's, as at the Queenstown Split US 301 had no control city. In addition to that at Middletown where US 301 used to turn left before DelDOT realigned the US 301 and DE 299 intersection, it did say "New York" for a control city on a span wire assembly before it was later changed to "Del. Mem. Br." So at least Wilmington is an improvement, even though its not the ideal place to use.
Also, for years the CBBT used "Philadelphia" for NB US 13 leaving the parking lot for the CBBT Fishing Pier and Gift Shop. Despite Salisbury, Dover, and Wilmington all lying before it, it is odd that it gets used at all coming from that point 4 miles out in the Chesapeake Bay.