Interstates or US Highways that go A-B-A in terms of states traveled

[AlexandriaVA]

In other words, the highway leaves state A, enters state B, but then the next state line it crosses is back to A.

Discounting beltways or other circumferential routes. Meandering rivers that serve as state boundaries might be a promising area to look at.

Apologies if this has come up before.

[AlexandriaVA]

Technically the GW Parkway meets this test:
1) Leaves Virginia and enters DC just west of I-395 (going onto Columbia Island, which is part of DC due to the fact that all of the Potomac River up to the Virginia side belong to DC/MD)
2) Leaves DC and re-enters VA just south of I-66.

[Rothman]

In other words, the highway leaves state A, enters state B, but then the next state line it crosses is back to A.

Discounting beltways or other circumferential routes. Meandering rivers that serve as state boundaries might be a promising area to look at.

Apologies if this has come up before.

I-86.  First!

[AlexandriaVA]

In other words, the highway leaves state A, enters state B, but then the next state line it crosses is back to A.

Discounting beltways or other circumferential routes. Meandering rivers that serve as state boundaries might be a promising area to look at.

Apologies if this has come up before.

I-86.  First!

Just looked on the map and wow! That's a close one but good catch.

I think like with mine, some local knowledge really helps with that one.

[CtrlAltDel]

What about something like I-24 in Tennessee, Georgia, and Tennessee?

[Rothman]

In other words, the highway leaves state A, enters state B, but then the next state line it crosses is back to A.

Discounting beltways or other circumferential routes. Meandering rivers that serve as state boundaries might be a promising area to look at.

Apologies if this has come up before.

I-86.  First!

Just looked on the map and wow! That's a close one but good catch.

I think like with mine, some local knowledge really helps with that one.

It's very well known on here.

[AlexandriaVA]

What about something like I-24 in Tennessee, Georgia, and Tennessee?

Yes, and looking at the map it reminds me a lot of the I-86 example.

[AlexandriaVA]

Looks like US-191 briefly goes into from Montana into Wyoming, and then back to Montana in Yellowstone NP

[plain]

Like US 50? MD→WV→VA→MD

And US 340 VA→WV→very briefly VA

[AlexandriaVA]

Like US 50? MD→WV→VA→MD

And US 340 VA→WV→very briefly VA

Wow - really good catch on US-50, and you're selling yourself short because you didn't include DC (yes, not a state but you get the point). That's a really brief stretch of the road in western MD

[MATraveler128]

I-684 crossing into Connecticut briefly from New York

[NWI_Irish96]

US 2 goes Michigan-Wisconsin-Michigan-Wisconsin

[froggie]

Pretty sure this has come up before.

A couple cases that come to mind offhand (besides those already mentioned):

• US 52/119 along the KY/WV border
• US 460 also does this, crossing into WV then back into VA, but spends over 20 miles in WV before crossing back

[TheHighwayMan3561]

US 212 MT-WY-MT-WY

[AlexandriaVA]

Pretty sure this has come up before.

I struggle to think of any interesting topic that hasn't at this point...

[Some one]

US 62/180 - Texas -> New Mexico -> Texas

US 71 -  Arkansas -> Texas -> Arkansas

US 59 - Texas -> Arkansas -> Texas -> Arkansas

[TheHighwayMan3561]

Pretty sure this has come up before.

I struggle to think of any interesting topic that hasn't at this point...

"What would you do for a Klondike bar?"

[JayhawkCO]

Why limit to Interstates and US Highways?

WYO70 WY->CO->WY

[tchafe1978]

US 2 from west to east, goes from Wisconsin, to Michigan, to Wisconsin, and back to Michigan again.

US 141 from south to north, goes from Wisconsin, to Michigan, to Wisconsin, and back to Michigan again, and all as part of a concurrency with US 2.

[SkyPesos]

US 395 CA-NV-CA

[jp the roadgeek]

NY 120A:  NY, NY/CT border, CT, border again (though mostly in NY), CT, NY.

NH 153: NH, ME, border, NH

ME 113 and 113 B:  ME, NH, ME

MA/RI 114A: RI, MA, RI

[MATraveler128]

Once upon a time, US 5 used to go from VT/NH/VT.

PA 611 at the time used to go from PA/NJ/PA.

[Great Lakes Roads]

MN 23

MN-->WI-->MN

[webny99]

US 2 goes Michigan-Wisconsin-Michigan-Wisconsin

Technically I-86 does this with NY and PA too, since it starts in PA.

[webny99]

What about something like I-24 in Tennessee, Georgia, and Tennessee?

Good thing I re-read the thread. Was about to exclaim that I couldn't believe this hadn't been mentioned. 

It's longer than the I-86 example, but seemingly not as well known or discussed as frequently for some reason. Maybe just northeast bias.