Closest same-numbered 3di pairs

[Pete from Boston]

It just occurred to me Massachusetts and Connecticut each have an Interstate 291 only 21 miles apart, never intended as part of the same road or anything of the like.

Where else do three-digit Interstates of the same number come this close? Is this the closest?

[froggie]

I want to say we've had a thread on this before, or at least a brief discussion in another thread, but yes that's the closest.  The 2nd closest would be I-695 DC/MD at 31 miles.