Routes or roads you used to cross state lines.

[US 89]

every time I have crossed a state line has been on an interstate except for:
...
tn-al us 31
...

That's also I-65, unless this was so long ago that I-65 didn't exist there yet...

[ctkatz]

^^in my defense, the road was called old us 31 and tracing old routes of us highways that's what I remembered it as since I don't remember seeing any reassurance signs on either side of the state line. that was at least 25 years ago so both tennessee and alabama could have put signs up since then.  I fixed that although us 31 still applies (correctly noted as part of I 65).

[fwydriver405]

With the MBB season over... updating to add more crossings based off this list:

CT/NY
I-684
I-84

NY/NJ
Garden State Parkway (NJ Route 444/Connector)

VA/DC
I-395 via the 14th ST and Rochambeau Bridge

DC/MD
Pennsylvania Ave (MD Route 4 on the MD side)
Baltimore-Washington Pkwy

[hobsini2]

I thought I had done this before but I can't find it so....I will work on this more.

IL/IN
I-74, I-80/I-94, I-90

IL/IA
I-80, I-280
US 20, US 30, US 34, US 52

IL/KY
I-24
US 51
IL 1/KY 91 (via Ferry)

IL/MO
I-55/I-64/US 40, I-70, I-72/US 36, I-270, I-255/US 50

IL/WI
I-39/I-90, I-41/I-94/US 41
US 12, US 14, US 45, US 51
IL 76/WI 140, IL 83/WI 83