Why it is called Four Corners

Four corners, one point

Every state has corners. What makes this one worth a name is that four of them are in the same place: the southwest corner of Colorado, the southeast corner of Utah, the northeast corner of Arizona and the northwest corner of New Mexico all land on a single disc. Most state boundaries in the United States follow rivers, ridgelines and older colonial charters, and those produce three-state corners at best. Straight lines produce this.

The name also gets used for the wider region — the Four Corners region, the Four Corners states — which is where a good deal of confusion starts. Two Mesa Verde tour descriptions mention a lookout over the Four Corners region, meaning a viewpoint tens of miles away from which you can see into all four states. That is the region. The marker is the point.

The corner exists because of a meridian that no longer exists

This is the part I find genuinely strange, and it is the reason this page exists at all rather than being one line long.

The north–south line that makes the corner was not drawn from Greenwich. The Colorado Organic Act of 1861 and the Arizona Organic Act of 1863 fixed it as the 32nd meridian of longitude west from Washington — the Old Naval Observatory in Washington, DC, which an Act of 28 September 1850 had made the American prime meridian. Congress did not repeal that until 1912. So the corner was positioned by measuring from a prime meridian the United States stopped using more than a century ago, and the surveyors who ran the lines were working from a reference point that no longer has any standing in federal law.

The wording outlived the meridian. Article I of the Colorado Constitution still quotes the 32nd meridian west from Washington verbatim, and Article I of New Mexico’s Constitution still defines that state’s western boundary the same way. A repealed prime meridian is still load-bearing in two state constitutions, which is why the gap between the marker and the described line is a conversion problem rather than a mistake. That story, including the widely repeated claim that the monument is 2.5 miles off, is on is it in the wrong place.

What you do about it

You drive out, pay US$8 per person at the gate, and stand on the only quadripoint in the country for half an hour. There is no advance ticket and no way to buy one. The four states, quadrant by quadrant, are on which four states meet; whose land it is, which is a separate and more interesting question, is on who owns it; and whether the drive is worth making from where you are is on is it worth it.

Frequently asked questions