If you mean the nearest points on both states to each other, the half way point is VERY close to the point where the borders of Ohio, West Virginia, and Kentucky meet each other.
If you mean from/to their capitals, (Trenton and Jefferson City) the midpoint is in Ohio.
I found this by looking at Google earth and using the "ruler" function.
I'm thinking Missouri.
The shortest and fastest route between those two places has a halfway point in Kansas. If you're traveling through Missouri, Prairie State Park is near halfway.
Bordentown, NJ
Columbus, NJ
The halfway point is in Great Meadows, NJ.
That's quite a drive. The halfway point is the Arkansas/Missouri state line.
What town is Halfway between flanders nj and tinton falls j
The halfway point between Allentown & Milton is Maple Hill, Pennsylvania
Youngstown, NJ.
Kenilworth, NJ
Lots of states start with "M." I'll assume you're going to Missouri. The halfway state is Indiana. Mooresville, to be precise.
The Oklahoma state line after you leave Missouri.