Arkansas SR-43

The stretch of road discussed here is probably the most unusual in the entire country.

OK-20 approaches the Oklahoma/Arkansas State Line from the west. AR-43 approaches from the east. They meet at the state line, roughly five miles south of Missouri, and start heading to the NNW, along the state line, as a duplexed road. (Other web sites say that OK-20/AR-43 is the only road in the country duplexed with SH's from different states, and who am I to argue?)

Now here's where it really gets interesting: this duplexed road goes along the state line for about four miles, then turns back into Oklahoma for almost the entire last mile. In the Terraserver satellite picture at left, the state lines are in yellow, the highway in question is in green. The section where the green line is to the left of the yellow line is the part we're talking about here, for in that section Arkansas State Highway 43 is located wholly within the state of Oklahoma!

As for why AR-43 just didn't stop back when it reached the border: continuity. Just after the road retouches the OK/AR state line, it crosses into Missouri, where it becomes their SH-43.

Southern Terminus: Oklahoma/Arkansas State Line, one mile SSE of the point where Oklahoma, Arkansas & Missouri connect

Currently traveling north along the state line. The point in which the road turns to the left is the spot where AR-43 becomes situated entirely within Oklahoma.

Northern Terminus: about 500 feet south of the point where Oklahoma, Arkansas & Missouri connect

I am taking this picture while standing right on the Arkansas/Missouri state line. Oklahoma is to my immediate right (couldn't stand right on the tripoint because there's a small obelisk there marking the point). The turn in the road is, again, where AR-43 goes entirely into Oklahoma. 

Some more pics:

Upper left: the aforementioned mini-obelisk, looking toward Arkansas. Missouri is the pie-wedge section at the left.
Upper right: the road as it appears in Missouri.
Lower left: the point five miles south of Missouri where OK-20 & AR-43 first meet, looking north along the state line (Oklahoma is to the left, Arkansas to the right). Note the signage error as AR-43 is signed here as MO-43, even though Missouri is still five miles away.
Lower right: the directional signs for the approaching intersection from the Oklahoma side. Another signage error: the sign for South MO-43 is actually where 43 goes wholly into Arkansas and never sees Oklahoma again. Still five miles south of Missouri, though.

Pictures taken 9 December 2002.