Grove City, PA
Along Primary Interstates: I-79, I-80
Along US Numbered Highways (<=5mi): US-19
Along Auxiliary Interstates: None
I-79
From: Cranberry, PA - 35.9 miles
To: Erie, PA - 68.4 miles
Diversion: 0.9 miles
From: Franklin Park, PA - 39.9 miles
To: End (Downtown Erie, PA) - 71.4 miles
I-80
From: Hermitage, PA - 21.5 miles
To: Falls Creek, PA - 82.1 miles
Diversion: 8.2 miles
From: Macedonia, OH - 84.8 miles
To: Bellefonte, PA - 147.7 miles
From: Strongsville, OH - 102.7 miles
Splits a 103.5 miles gap from Cranberry, PA to Erie, PA, and will make I-79 super-complete by reducing the largest gap to less than 100 miles.
It's a large diversion off I-80, but I suppose it could be used heading west if people aren't quite sure if they can make Hermitage, PA.