West Virginia
Maryland
This highway was created as a toll-free alternative to the Pennsylvania Turnpike.
I-68's designation was originally intended for the US 50 freeway between Washington, DC and Annapolis, MD. However, I-595 was the number assigned to the freeway, and I-68 ended up as a replacement for US 48 (which has since reappeared as a new surface road in Virginia and West Virginia).
In the future, I-68 might be extended into Ohio, ending at either Dayton or Cincinnati.