Longest common US border?

Which two states of the United States share the longest common border?

I have no figures, but from eyeballing it, California-Nevada looks like the longest.

Texas-Oklahoma and Texas-New Mexico seem like the only other contenders.

California-Nevada might be deceptive, because the border is 2 relatively straight lines.
Idaho-Montana might be a possibility. Or even 2 rather small states with very jagged borders…like West Virginia and Virginia or something. It all depends.

Considering river borders, Illinois/Missouri might be a contender. Some river bends are miles long, but only amount to a fraction of a mile in net distance.

For straight line borders, CA/NV looks like it. It’s about 626 miles; TX/NM is only about 512.

We could start bringing fractals into the measurement and then we’ll never know how long anything is!

A quick measurement using a map indicates CA-NV as about 620 miles… easy to measure since it’s straight lines. The TX-OK border appeared to be about 620 miles as well… but I approximated the eastern part of the border (Red River)with a couple of line segments. The real border is undoubtedly longer. So I suspect the Texas-Oklahoma border is the longest. I don’t think any jagged boundaries between other states are jagged enough to make a difference. Idaho-Montana is probably up there, though… maybe 580-600 miles. Unfortunately, my map is small-scale (1:7,500,000).

Is that so…

[sup]gets a tremendous ego boost[/sup]

According to this site (or is that cite? ;)):

http://www.econ.umn.edu/~holmes/data/BorderData.html

…containing this table…

http://www.econ.umn.edu/~holmes/data/BORDLIST.html

…of the 109 borders existing in the U.S. the Texas-Oklahoma border appears to be the longest by quite a safe margin at 715.4 miles. Followed by CA-NV (608.2 miles), ID-MT (569.8 miles), and NM-TX (536.2 miles).

I’m not entirely sure how the author got the data, or made the data calculations. Perhaps the distances aren’t a true analog measurement, but with a difference of over a hunderd miles its probably safe to bet that if you took both borders precisely TX-OK would still end up on top.

It looks like the author figured out the distances by looking at each border as a series of line segments. So far Oklahoma-Texas, he had to have some sort of info that measures each bend in the Red River.

According to this chart, http://www.econ.umn.edu/~holmes/data/bordpnts.asc

there are 31 distinct line segments in the TX-OK border.

Lets also keep in mind that it will depend what type of projection the author used to make his measurements.

Here’s a site where you would be able to calculate the more precise TX-OK border.

http://www.texasalmanac.com/texasenviro_2000.htm

Notice they give both general estimates and a second set of measurements that include the smaller meanderings of the rivers and coast.

I didn’t do the match to add up the border, but notice that the Red River border goes from 480 to 726 miles.

This might bring MT-ID closer to the front when you consider the larger ratio of border comprised of river bends.

A really tiny hijack:
Lets point out the while the Alaskan border doesn’t contact another state, its border with Canada is clearly the longest in the states.