Mystery of the Mexican Quadripoint

Does México have a quadripoint? That’s not intended as a trick question. Ideally this should have an easily verifiable solution. Either four Mexican states touch at a common spot — a quadripoint — or they do not. The answer however is considerably more elusive. I remain at a loss as I attempt to uncover whether someone should reasonably conclude one way or the other.

There are a couple of candidates, and the Mexican states of San Luis Potosí and Zacatecas are common denominators.

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Notice the relative proximity of the states of Jalisco, Guanajuato, San Luis Potosí, and Zacatecas. A small notch of Zacatecas protrudes just far enough south to prevent Jalisco and San Luis Potosí from sharing a common border according to Google Maps, with all of the usual caveats about the accuracy of Google Maps. The situation seemingly separates the two states by about 1.88 kilometres (1.17 miles) according to my quick calculation.

This is an agricultural area farmed and ranched fairly intensively judging by satellite mode and confirmed by proximal Street View availability (sample image). There’s even a ranchero within the Zacatecas notch, which would be an interesting geo-oddity homestead for the lucky resident: a click east to San Luis Potosí; a click south to Guanajuato; a click west to Jalisco. It’s easily accessible from the nearest town, Ojuelos de Jalisco, less than 12km down a road called Deportiva (which translates to "sports" and runs by the town’s athletic fields as it departs town). A driver would also cross the border between Jalisco and Zacatecas a couple of times for good measure too (map).

This happy confluence of multiple borders didn’t seem to be controversial. It did in fact appear to represent two tripoints falling in very close proximity to each other. A cube of Zacatecas less than 2km on a side blocked a rare opportunity for a quadripoint.

The other potential Mexican quadripoint takes place in the vicinity of Coahuila, Nuevo León, San Luis Potosi and Zacatecas either where they all join together or where they all nearly do so, depending on the evidence one chooses to accept.

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Google Maps sides clearly with the camp that believes in two tripoints in close proximity to each other rather than a single quadripoint, once again considering that Google isn’t the arbiter of all things geographic. However, notice the distance between to two tripoints: 12.17 km (7.56 mi). It would hardly seem to be a question with such a sizable gap. Yet, other maps are much less clear including some published by the Mexican government. The Yahoo! Group "boundarypointpoint" which specializes in just these types of situation appeared to have reached a consensus that a quadripoint did not exist, after lengthy discussions and earlier research.

However, a monument exists at what many would call the northern of the two tripoints, the "Mojonera de los Cuatro Estados" (Marker of the Four States). There are various photographs of the marker posted on the Intertubes although none that I could find with Creative Commons licensing so I couldn’t embed them here. Feel free to open a photo from Panoramio or from Flickr in another tab and observe the results. The marker would be readily accessible albeit after enduring a jarring 8.1 km (5.0 mi) ride down a rough road. I think the guy in the Flickr image with the mountain bike had the right idea.

Wikipedia bought into the idea of a Mexican quadripoint, for what that’s worth. It was presented as fact without citing any evidence, and was immediately flagged as such. Wikipedia attempted to weasel-word around the issue by stating that this is the place where the four states "effectively" meet. Right. I’m not sure de facto or close-enough provides a decent standard for a concept that implies precision. Even the contributors on boundarypointpoint seemed conflicted after the revelation of the Mojonera de los Cuatro Estados.

Examining the Mexican Geological Service website, Servicio Geológico Mexicano, provided nothing definitive and Internet searches using the Spanish-language term "Cuadripunto" yielded no better results either.

Was it a situation created by imprecise surveying techniques like the Delaware Wedge? Is it so rural and effects so few people that the governments involved simply don’t consider it enough of a priority to figure it out? Or has it been overtaken by events with a named boundary stone, the Mojonera de los Cuatro Estados, converting a close-enough approximation to an exact declaration?

In my mind, the elusive Quadripoint of México remains a mystery.

Jalisco’s Ghostly Hand and Bony Fingers

My efforts to update each one of hundreds of customized maps to the current version of Google Maps has been an ongoing chore. Not every aspect has been without benefit though. For instance it allowed me to ponder my complete index of places featured on the Twelve Mile Circle in more detail than I’ve done in a long time. I felt pretty satisfied with my five-year effort until I noticed the wasteland of 12MC content "South of the Border." Then my obsessive-compulsive nature began to drive me. Must… add… pushpins… to… México.

That could be challenging. I didn’t have anything for México in my backlog of potential topics. Maybe I could stare at a map for awhile in desperation and hope that something might appear. Eventually and much longer than I would care to admit, I noticed a strangely-shaped object, an odd protrusion sprouting from the northern end of Jalisco. Officially Jalisco is the "Estado Libre y Soberano de Jalisco" which translates to a very prestigious-sounding Free and Sovereign State of Jalisco. This Mexican state included noteworthy cities such as Guadalajara and Puerto Vallarta although those won’t be mentioned again. That’s just for reference.

Check this out:

Municipalities map of Jalisco
Wikimedia Commons via Creative Commons Attribution 3.0 Unported (CC BY 3.0) license

Behold the magnificence of what looks like a ghostly hand, or maybe more accurately a paw, with three primary fingers and a couple of small gnarly stubs sprouting from the main body of Jalisco. Each of the sub-units is a separate municipality, a second-level division of government in México somewhat analogous to a county in the United States. There are 2,438 municipalities in México with 125 of them found in Jalisco. Plenty of people count counties in the United States. I wonder if anyone counts municipalities in México? Sadly my lack of Spanish linguistic skills precluded finding out.

I dug a little further to identify the specific municipalities within Jalisco’s hand.

  • Wrist: San Martín de Bolaños
  • Palm: Bolaños; Chimaltitán; Villa Guerrero; Totatiche
  • Palm and Middle Finger: Mezquitic
  • Left Finger: Huejuquilla el Alto
  • Right Finger: Colotlán; Santa María de los Ángeles; Huejúcar

Totatiche en canícula
palabrista on Flickr via Creative Commons Attribution-ShareAlike 2.0 Generic (CC BY-SA 2.0) license

This image from Flickr provided a nice overview of the terrain within Jalisco’s paw. It was taken within the municipality of Totatiche, part of what would be the palm in my twisted Rorschach interpretation of the shape.

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I honed-in on a narrow neck that connected the unusual protrusion to the rest of Jalisco. The width narrowed-down to approximately 2.9 miles (4.7 kilometres) in a couple of different places, almost pinched completely through by the neighboring states of Zacatecas and Nayarit. The fingers abutted Zacatecas primarily, and in turn defined a Zacatecas "claw."

The constriction reminded me of a similar situation in the U.S. state of Maryland which narrows to 1.4 miles (2.3 km). The primary difference, though, is that the northern hand of Jalisco appeared to be a practical exclave. I could not detect any signs of a road or a track or a path that remained within the state to provide transit through the full length of the constriction. Anyone wishing to travel to the northern part of Jalisco overland other than by foot would need to cut through one of its neighboring states.

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I wish I could discover how the shape came into existence. It didn’t appear to follow a riverbed or specific land contour. I know it’s old. The layout existed at least as early as the Viceroyalty of New Spain (1786-1821) according to a map in the Perry-Castañeda Library collection.

Tangentially related

Come to think of it, the shape of neighboring Zacatecas was odd too (map). It reminded me of a troll hunched over, hands folded behind him, stomping through central México and about to crush the city of San Luis Potosí.

The Zacatecas claw was also a practical exclave.

Feel free to provide your best interpretations for the shapes of Zacatecas or the Jalisco protrusion.