It Enters then Exits

On April 15, 2010 · 7 Comments

I noticed an interesting anomaly as I returned from my recent trip down south. I considered a variety of paths before settling on my ultimate course. I nearly selected one of the other finalists but I turned it down at the last minute in favor of some back-roads through rolling countryside. Had I followed that original choice it would have taken me through a little slice of Georgia.

View Larger Map.

This tiny sliver of Interstate 24 enters Georgia, arcs southward, and departs Georgia only 4.1 miles (6.6 kilometres) later. It makes perfect sense. The road engineers wanted to build their route through flatter terrain while avoiding the hills within the more direct path. That simplified their construction and pushed the road just below the Tennessee-Georgia border ever-so-briefly to create our interesting byproduct.

That got me thinking. What is the shortest segment of Interstate highway in the United States that traverses a state? In other words, one that enters and exits a state as a contiguous, numbered Interstate highway.

I’d been aware of other short segments that fit the general definition. I’ve driven Interstate 95 through Delaware (23.43 mi / 37.7 km) and New Hampshire (16.11 mi / 25.9 km) and I’d always thought both of those were really short. They are, but they pale in comparison to Georgia’s portion of I-24. I do give all due credit to Delaware and New Hampshire for both setting up toll booths along their minuscule borders to gouge travelers heading to final destinations involving neither of them. How nicely parasitic of them.

The Georgia example along I-24 is good but it’s not the best. We can find shorter. I know I’d have an amazing answer if the government ever sewed a 51st star on the U.S. flag by making Washington, DC a state. It’s one of my favorite geo-oddites.

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Interstate 495, the famous Capital Beltway, barely clips the waters of the District of Columbia as it crosses the Potomac River on the Woodrow Wilson Bridge. The total distance measures to 0.11 miles (0.18 km). Too bad DC isn’t a state. It doesn’t count.

I consulted the Federal Highway Administration of the U.S. Department of Transportation. They provide a number of resources including their FHWA Route Log and Finder List. Now, if I were truly motivated I’d crosscheck every one of those short segments on a map to determine the shortest one that traversed a state, versus those that are simply short access spurs into cities. Maybe someone will peruse that list in detail some day and answer that question definitively. That won’t be me, at least not today.

I did check a couple of promising possibilities and stumbled across a really good one: Interstate 684 in Connecticut.

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I-684 leaves New York, clips Connecticut and returns to New York. That’s a stretch of only 1.4 miles (2.3 km), and it’s going to be a tough distance to beat. It’s so short that there isn’t even a Connecticut exit. Most drivers probably don’t even realize they’ve left New York albeit very briefly.

I consulted Steve of the renowned Connecticut Museum Quest. He knows everything about everything in Connecticut. I do that from time-to-time to see if I can stump him with some totally obscure point of Connecticut geo-trivia. I failed as miserably as usual. Not only was he aware of the anomaly but he’s driven it. Multiple times.

He also offered Interstate 84 at the NJNYPA tripoint as an “honorable mention.” I drove this road and visited the New Jersey highpoint last summer, so I do have some basic familiarity with the area.

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The Interstate comes oh-so-close to clipping New Jersey, and if it did it would eclipse even the Washington, DC example. Sadly it falls just a few feet onto the New York side of the line.

On April 15, 2010 · 7 Comments

7 Responses to “It Enters then Exits”

  1. Greg says:

    There’s also I-86, the Southern Tier Expressway in New York, that dips into Pennsylvania in Waverly/South Waverly NY/PA. I’ve driven it many times, and I’d be surprised if it was a mile altogether, but I’m too lazy to measure it.

    View Larger Map

    Also: ever been to the Pratt Street Ale House in Baltimore? I was just there yesterday; pretty good.

  2. Kandice says:

    Interstate 86 dips down briefly into Pennsylvania here for about 1.2 miles:

    It’s marked with State Border signs:

    There’s a couple caveats to this segment though. First, I’m not sure of the actual distance, the borders on Google maps are a bit off, so it may be longer than I-684, but it is in the ballpark, at least. Also, I-86 reenters Pennsylvania near Erie. While your definition didn’t bar reentry, the fact that it does reenter makes it a bit less “pure” than I-684, but still interesting nonetheless.

    Love the blog! 😀

    • A Note on Interstate 86 and the Dip Into Pennsylvania

      First and formost, thank you Greg and Kandice for pointing this out. I hadn’t been aware of the peculiarity and it’s an exciting discovery. Seriously. I love this stuff. It would absolutely count in my opinion even with the vestigal tail in Erie, PA.

      The segment doesn’t yet show up in the FHWA mileage figures (referenced above) so I dug a little deeper into the situation. This section of New York Route 17 is either in the process of being upgraded to Interstate standards or has just completed that process. If it’s been completed — and Google Maps thinks it’s done but other sources including Google Street View beg to differ — then it will certainly join the ranks of the extremely short traversers and perhaps become the reigning monarch of the list. I also measured it at about 1.2 miles so our unscientific sample size of two at least seems to be consistent. It will probably take the Intertubes awhile to catch up with reality so any readers from the Elmira, NY area should feel free to check it out and provide an on-the-ground report.

      GREG r.e., Pratt Street Ale House: I’ve not had an opportunity to visit there but it’s mentioned frequently on the DC-Beer listserv as a place to go. Someday I will. In the meantime, give me a shout if your travels happen to take you just a little further south.

  3. Matthias says:

    Awesome post about a completely new to me geo oddity!
    You hadn’t done one like that in weeks 😉

  4. mike says:

    Speaking of the vestigal tail of I-86 n Erie, PA (where I’m located) here’s a question for you:

    what counties have the greatest number of interstate beginnings/ends that travel outside of that county?

    I know Erie County PA has two. (I-86 and I-79)

    I’m betting there are many others in higher populated areas that have quite a few, but how many if you don’t count spurs or beltway types (2-digit interstates)?

  5. Greg says:

    Matter of fact, I will be in the District tomorrow, but I’ll be on a tight schedule. Also: what about doing this search for stretches of road that enter and then exit a *country*? We get pretty interesting here. Major roads or all roads no matter the size? Are claves allowed or not? Early contender, if we’re sticking to major roads without claves: the A3/N54 in the UK/Ireland.,-7.297325&spn=0.048462,0.110035&z=13

    There are minor roads in the immediate vicinity that make for much shorter stretches as well.

  6. Joshua says:

    With regard for I-684 in CT, there is a small sign saying “Entering Greenwich Connecticut,” and then “Leaving Greenwich Connecticut.”
    Look towards the bottom of this page.

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