Interstate Highway Time Zone Crossings

On April 6, 2014 · 7 Comments

I’ve been noticing search engine queries lately seeking additional information about points along US Interstate Highways where travelers cross from one time zone into another. I’m going to do that myself soon on my upcoming trip and I couldn’t find a comprehensive resource either. Maybe there’s one out there hidden away in a lonely corner of the Intertubes. Maybe not. I didn’t see it so I decided to create my own. Hopefully others will find this compact reference useful too.

Yes, I understand that mobile phones and other networked devices grab time changes automatically without human intervention from nearby cell towers as one drives merrily down the highway. However some of us like to by hyper-prepared before embarking on a journey. I even recorded the lat/long coordinates so travelers (OK, maybe just me…) could drop the waypoints into their GPS receivers and know exactly where the time change would happen well in advance.

View Interstate Highway Time Zone Changes in a larger map

Readers will want to open this map in another tab or window. It’s not very useful in its present scaled down version that is included for illustrative purposes. Others may prefer the even more detailed Google spreadsheet with links that I prepared. The spreadsheet layout mimicked the geographic footprint of the United States in rough terms, for example I positioned Idaho at the top-left (northwest) and Florida at the bottom-right (southeast). That was also the reason why Interstate numbers on the spreadsheet and the lists below were ordered from large to small (I-94 to I-8). I didn’t reverse the order just to be obstinate. Even-numbered Interstates run roughly west to east across the nation with the 2-digit numbering increasing from south to north. There were also a handful of odd-numbered highways that crossed time zone boundaries too and muddied the construct a bit. Again, the rules applied in general terms only.

This exercise was a lot more tedious than I imagined. Believe me, I’d use much more colorful language if this wasn’t a family-friendly website. I’d assumed quite foolishly that the preponderance of time changes would happen at state borders, and simplify my task. Some do, although many more switch at random county borders which were much more difficult to pinpoint on a map. That’s why I think people have trouble tracking time zones as they drive. Now they have a tool — this page.

Here’s what I found. I’m sure errors or omissions crept into this because it was such a pain to compile. Please let me know and I’ll make corrections.

Change Between Pacific Time and Mountain Time

  • Interstate 90: Idaho <--> Montana
  • Interstate 84: Baker Co., OR <--> Malheur Co., OR
  • Interstate 80: Unincorporated Elko Co., NV <--> West Wendover, Elko Co., NV(1)
  • Interstate 40: California <--> Arizona (Standard Time); Eastern Arizona <--> SE corner of Navajo Reservation in AZ (Daylight Saving Time)(2)(3)
  • Interstate 15: Nevada <--> Arizona (Standard Time); Arizona <--> Utah (Daylight Saving Time)(2)
  • Interstate 10: California <--> Arizona (Standard Time); Arizona <--> New Mexico (Daylight Saving Time)(2)
  • Interstate 08: California <--> Arizona (Standard Time); no change during DST(2)(4)

Change Between Mountain Time and Central Time

  • Interstate 94: Stark Co., ND <--> Morton Co., ND
  • Interstate 90: Jackson Co., SD <--> Jones Co., SD
  • Interstate 80: Keith Co., NE <--> Lincoln Co., NE
  • Interstate 70: Sherman Co., KS <--> Thomas Co., KS(5)
  • Interstate 40: New Mexico <--> Texas
  • Interstate 10: Hudspeth Co., TX <--> Culberson Co., TX

Change Between Central Time and Eastern Time

  • Interstate 94: Indiana <--> Michigan
  • Interstate 90: LaPorte Co., IN <--> St. Joseph Co., IN(6)
  • Interstate 85: Alabama <--> Georgia(7)
  • Interstate 80: LaPorte Co., IN <--> St. Joseph Co., IN(6)
  • Interstate 74: Illinois <--> Indiana
  • Interstate 70: Illinois <--> Indiana
  • Interstate 65: Jasper Co., IN <--> White Co., IN /AND/ Hart Co., KY <--> Larue Co., KY(8)
  • Interstate 64: Perry Co., IN <--> Crawford Co., IN
  • Interstate 59: Alabama <--> Georgia
  • Interstate 40: Cumberland Co., TN <--> Roane Co., TN
  • Interstate 24: Marion Co., TN <--> Hamilton Co., TN
  • Interstate 20: Alabama <--> Georgia
  • Interstate 10: Jackson Co., FL <--> Gadsden Co., FL

Bonus Roads(9)

  • Western Kentucky Parkway: Grayson Co., KY <--> Hardin Co., KY(10)
  • Cumberland Parkway: Russel Co., KY <--> Pulaski Co., KY(11)


(1) West Wendover is the only part of Nevada that officially observes Mountain Time, primarily so gamblers from Salt Lake City — the nearest large town — won’t have to deal with a time change and can focus on losing their money without distraction. This was described in (West) Wendover: What Time? What State?
(2) Arizona does not recognize Daylight Saving Time, meaning that for practical purposes the spot where the time zone change takes place shifts in the Spring and the Fall. This can sometimes lead to embarrassing situations.
(3) The exception to the "Arizona doesn’t recognize DST rule" is the portion of the sprawling Navajo Nation that crosses into Arizona. The Navajo did this to assert their sovereignty as well as to keep their tri-state Nation on the same time all year.
(4) Interstate 8 extends from San Diego, California to south-central Arizona; fairly short by interstate standards. Therefore it does not experience a time change when the two states observe the same time (i.e, when the Pacific Time Zone switches to DST and Arizona remains on Mountain Standard Time)
(5) I crossed this one during my Dust Bowl trip. See Kansas Mountain Time.
(6) You’re not seeing things. Interstates 80 and 90 are repeated with the same information here. That’s because they’re co-signed at this spot.
(7) Interstate 85 is the best example of an odd-numbered Interstate messing up my chart. The time change happens at a very southern segment of this very eastern highway.
(8) Interstate 65 starts in Central Time in an Indiana suburb of Chicago, switches to Eastern Time as it heads south, then switches back into Central Time in Kentucky
(9) I included Kentucky parkways because they’re significant roads albeit they’re not Interstate highways (not even Secret Interstates). I probably could have added other roads too.
(10) I will be crossing here on an upcoming trip. This was the spot that inspired me to go ahead and compile the list.
(11) I crossed here in the summer of 2013 during my Kentucky Adventures.

Largest Artificial Lakes

On July 16, 2013 · 2 Comments

I had some fun with artificially created geographic features lately, first with the largest artificial islands and then with islands joined artificially to the mainland. Now, I thought, I’d flip the concept to its opposite extreme. Instead of land on water, how about water on land? What might be the largest area of terrain intentionally flooded to make an artificial lake or reservoir?

My continuously growing bag of possible topics might come in handy, I though. This was my big spreadsheet that I use to tally new bits of geo-trivia as I come across them, most of which will never see the light of day on Twelve Mile Circle. Yes, I did seem to recall something. Ah, here it was: according to the CIA’s World Factbook, "Lake Volta is the world’s largest artificial lake by surface area (8,482 sq km; 3,275 sq mi)."

That introduced a quandary. Did "largest" mean a measurement of area or volume? Would it mean the list might change with fluctuations in rainfall or during times of drought? Those were not issues with islands. Islands weren’t measured by volume. Their surface area might changed slightly due to tides or erosion although probably not significantly assuming proper maintenance. Reservoirs, however, could change drastically by size or volume repeatedly during their lifetimes. Suddenly, something so simple in my mind became much more complex as it unraveled.

I did learn a couple of new terms in the process, though. "Conservation Pool" is an optimal level that meets the needs for which the reservoir was created. "Flood Pool" is the absolute maximum a reservoir can hold. The two values often differed drastically. Most of the calculations used in rankings, as far as I could tell, seemed to rely on the flood pool rather than the conservation pool as a means to preserve consistent measurements. That’s what I tried to use too.

It still didn’t answer which "largest" I should use so I decided to examine both: size as defined by square kilometres and volume as defined by cubic kilometres. Ponder that for a moment, a cubic kilometre of water!

Lake Volta

LAKE VOLTA. by Fraser Morrison, on Flickr
via Creative Commons Attribution-NonCommercial-NoDerivs 2.0 Generic (CC BY-NC-ND 2.0) license

Lake Volta in Ghana had the largest area that I could find, the 8,482 km² mentioned previously (other sources listed it slightly differently, an issue I found with all bodies of water examined). That made it larger than the land area of the U.S. states of Rhode Island (2,706 km²) and Delaware (5,060 km²) combined, or more than fifty times the size of the District of Columbia. That’s a seriously large man-made lake.

View Larger Map

The damming of the White and Black Volta Rivers in 1965 caused the displacement of literally tens of thousands of people. On a more positive side, Volta’s Akosombo Dam generated electricity for most of Ghana and created a thriving fishing industry.

Lake Kariba

HX9V_DSC03096_Farewell Lake Kariba
HX9V_DSC03096_Farewell Lake Kariba by Allan_Grey, on Flickr
via Creative Commons Attribution-ShareAlike 2.0 Generic (CC BY-SA 2.0) license

As I think about it, volume would probably be a more important indicator of size than area. A reservoir exists to store fresh water, and the more it can store for the needs of a surrounding population, the better. The largest volume of any artificial lake is Lake Kariba which straddles the Zambia and Zimbabwe border, with a storage capacity of 181 km³.

Lake Kariba

That’s an almost unimaginably large number as I considered it some more. Sure, it pales in comparison to an ocean, however, this particular body of water was created by people.

The lake filled what was known previously as the Kariba Gorge when the Zambezi River was dammed in 1958. Today its shores appear to be a great location for African safaris based on the online sources and photos I encountered as I researched it further.

Lake Sakakawea

Shoreline of Lake Sakakawea at Fort Stevenson State Park, North Dakota
Shoreline of Lake Sakakawea at Fort Stevenson State Park, North Dakota by loyaldefender2004, on Flickr
via Creative Commons Attribution 2.0 Generic (CC BY 2.0) license

I then turned my attention to the United States to see how it compared — not very favorably as it turns out versus the monster-sized international contenders.

North Dakota’s Lake Sakakawea on the Missouri River took the prize for largest area in the US.

Lake Sakakawea

Its 1,546 square kilometres seemed impressive until placed against Lake Volta’s 8,482 km².

On a completely irrelevant tangent, Wikipedia included an essentially meaningless statement which fascinated me anyway because I’m drawn to odd claims:

The creation of the lake displaced members of the Fort Berthold Indian Reservation from the villages of Van Hook and (Old) Sanish… one name that had been proposed [for a new town of displaced residents] was Vanish (a portmanteau of the two previous towns’ names).

I so desperately wanted to confirm that claim — everyone knows how much I love a good portmanteau — however Wikipedia offered the statement without attribution. I found one possible source although it offered little evidence that Vanish was anything other than a tongue-in-cheek proposal. I guess it would have been too good to believe that Van Hook and Sanish would vanish to (nearly) form Vanish.

The media wittily called the new town Vanish, a play on Sanish’s name and its unavoidable fate, but there’s no “Vanish, ND” on the maps today. When you lay the map… over nearby towns to figure out which one this is, you realize that the government was far less witty than the newspapers. The powers-that-be named the new town… New Town.

Lake Mead

Lake Mead
Lake Mead by Kath B, on Flickr
via Creative Commons Attribution-NonCommercial 2.0 Generic (CC BY-NC 2.0) license

Lake Mead is the US’s volume leader at 35.7 km³ which would hardly make a dent in Lake Kariba’s 181 km³ even though it’s still a massive amount of water.

Lake Mead

Lake Mead formed behind the Hoover Dam on the Colorado River and straddles the border between Arizona and Nevada. The lake also served as a good example of difference between capacity measurements, conservation pool vs. flood pool. It’s depth has fluctuated wildly during protracted drought cycles and has flirted with critical shortage levels in recent years.

I thought about including examples from other nations represented by 12MC readers. The area/volume dichotomy doubled my writing requirements and I began to lose interest.

Little Miss Muffet

On July 2, 2013 · 1 Comments

A map peculiarity reminded me of an old nursery rhyme, probably one of the most famous of them all, and likely familiar to each of us:

Little Miss Muffet
Sat on a tuffet,
Eating her curds and whey;

I’ll get to the specific reason soon enough. Let me ramble and meander for a little while though, as I tend to like to do, before arriving at the final destination.

The "Oxford Dictionary of Nursery Rhymes" would seem like a proper place to search for an explanation, however it’s copyright protected on Google Books and I didn’t feel like traipsing down to a physical library to look it up. An amalgam of different online sources, seemingly all deriving from Oxford anyway, traced a possible explanation to one Dr. Thomas Muffet who allegedly wrote the rhyme about his stepdaughter Patience. That’s one theory, anyway.

Black Widow Spider
Black Widow Spider by Smithsonian, on Flickr,
via Creative Commons Attribution-NonCommercial 2.0 Generic (CC BY-NC 2.0)

Dr. Muffet was an entomologist, an insect scientist, so that could have parlayed into the latter part of the rhyme where the spider frightened the little girl. Yes, I understand that a spider is an arachnid not an insect, and a spider scientist is an arachnologist not an entomologist. I’m grasping at straws, here. Regardless, the passage first appeared in published form in 1805, in "Songs for the Nursery."

There might also be a little intrigue or alternate meanings written into the verse:

Is Little Miss Muffet a symbol of sexual harassment or feminine stereotypes? Is this a simply a verse about a young girl eating a meal and being frightened by a bug? Or could these characters represent real people prominent in 16th century England’s history?

Do any of these explanations have anything to do with geography, and does 12MC really care? No, not really. It was a fun tangent while it lasted and let’s get back to more pertinent business.


Muffet, as a surname, "usually originates from the town of Moffat in Annandale, in the former county of Dumfriesshire, Scotland. If so the derivation is from the Gaelic ‘magh’, meaning a field or plain, and ‘fada’, translating as ‘long’, – the long field."

Moffat, Dumfries and Galloway, Scotland

It’s not a particularly common surname although the variant Moffatt (like the town) would probably sound more familiar. Geographically, I found a small handful of Muffets used as street names and that was about it.

View Larger Map

I decided to select Muffett Street, in Scone, New South Wales, Australia. I figured Miss Muffet might enjoy a nice scone once she tired of curds and whey. Scone is the horse capital of Australia, located in NSW’s Upper Hunter Shire of the Hunter Valley. The town is know primarily for the Scone Cup, "the biggest country racing carnival in Australia."


What, exactly is a tuffet? It’s a type of low-slung chair that most people would call a stool if it wasn’t covered with fabric. This is a tuffet:

tuffet and chair
Tuffet and Chair by triesquid, on Flickr,
via Creative Commons Attribution-NonCommercial-ShareAlike 2.0 Generic (CC BY-NC-SA 2.0) license

I don’t understand why anyone would publish such an ugly, shaggy example of a tuffet on Flickr, much less share it with a Creative Commons license. Nonetheless someone did and I’m grateful because ultimately tuffet was easier to show than to explain. The word also had an interesting etymology that derived from the Old French touffel, meaning little tuft, and it has become "obsolete except in the nursery rhyme."

View Larger Map

It’s pretty obsolete as a place name, too. The only geographic feature in the United States, Canada the United Kingdom or Australia that I could discover was a single lonely little pond in the Arizona desert: Tuffet Tank. It didn’t look anything like a tuffet. What could have influenced someone to call it a tuffet? I could see elbow or boomerang or even a cheezy mustache, but I’m struggling with tuffet.

Curds and Whey

Curds and Whey are odd consumables derived from milk, or substances seemingly more appropriate for an episode of Bizarre Foods.

Curds are a dairy product obtained by curdling (coagulating) milk with rennet or an edible acidic substance such as lemon juice or vinegar, and then draining off the liquid portion. The increased acidity causes the milk proteins (casein) to tangle into solid masses, or curds. The remaining liquid, which contains only whey proteins, is the whey.

I can say from first-hand experience that curds can be quite tasty. I’ve had cheese curds many times when visiting the wife’s family in Wisconsin. Curds, as served to me, were either plain or breaded and deep-fried as a bar snack. We called them "squeaky cheese" when they were particularly fresh. Some of you will know exactly what I mean. The rest of you will have to take my word for it that curds make a peculiar, unmistakable squeak when chewed fresh.

I don’t know anything about whey. I’ve never tried it.

View Larger Map

Finally, 12MC arrives at the entire point of this article, the spectacular Curdsen Way in Las Vegas, Nevada. I am convinced that this street was named for curds and whey. Look at the other street names nearby — Better Way? Thata Way? and… Supreme Court?… which is how I discovered the neighborhood in the first place. I purposely avoided this specific Supreme Court in the earlier article because I didn’t want anyone to spot Curdsen Way and spoil the surprise. I was laughing too hard.

That was one seriously messed-up real estate developer.

And that was an awful lot of reading to get to a punchline.

12 Mile Circle:
An Appreciation of Unusual Places
Don't miss an article -
Subscribe to the feed!

RSS G+ Twitter
RSS Twelve Mile Circle Google Plus Twitter
Monthly Archives
Days with Posts
April 2014
« Mar