On any standard map, Colorado looks like a neat quadrilateral box, bounded cleanly by lines of latitude and longitude. Mentioned on paper as a textbook rectangle, the Centennial State actually defies this simple geometric label. Surveying errors, the curvature of the Earth, and 19th-century political compromises mean that Colorado possesses 697 distinct sides, making it a technical polygon known as a hexahectaenneacontakaiheptagon. Understanding Colorado's borders requires looking past flat atlas pages and examining the real history of Western land mapping.
The Myth of the Rectangular State
For generations, maps have portrayed Colorado, Wyoming, and Utah as geometric blocks cut with mathematical precision. When the U.S. Congress established the Colorado Territory in 1861 and admitted it as a state in 1876, lawmakers defined its boundaries along exact meridians and parallels. The eastern and western borders were anchored to the 102nd and 109th meridians west, while the northern and southern edges followed the 41st and 37th parallels north.
However, mapping software and modern GIS data reveal that lines drawn on flat paper do not translate cleanly to a three-dimensional globe. Because the Earth is an oblate spheroid—bulging slightly at the equator and flattened at the poles—lines of longitude converge as they stretch toward the poles. Consequently, Colorado's northern boundary is roughly 22 miles shorter than its southern boundary, turning the state into an isosceles trapezoid rather than a true rectangle.
19th-Century Surveying Realities
The primary driver behind Colorado's 697 sides comes down to human error and the limitations of 19th-century surveying equipment. Crews working under the General Land Office had to haul heavy chains, magnetic compasses, and transit scopes across rugged mountain ranges, deep canyons, and arid plains. Further insights regarding the matter are covered by Associated Press.
When surveyors set out to mark these theoretical lines on the ground, minor miscalculations compounded over dozens of miles. Several notable deviations stand out in official land records:
- The La Sal/Paradox Deviation: Along the western border with Utah, surveyors missed their intended path across an eight-mile stretch, straying westward before correcting course, creating a notable jog.
- The Edith Deviation: On the southern border with New Mexico, the line swerves south near the community of Edith to follow a natural valley before resuming its eastward trajectory.
- The Wyoming-Nebraska Corner: Small kinks and adjustments accumulate where state lines meet, multiplying the total number of segments into hundreds of tiny straight-line fragments.
Historical records and boundary markers are detailed by the Bureau of Land Management, which oversees public lands and maintains the official baseline surveys across the American West.
Surrounding Neighbors and Territorial Touchpoints
Colorado shares its borders with seven different states, creating a complex web of regional intersections. To the north lie Wyoming and Nebraska, to the east sits Kansas, to the southeast touches Oklahoma, to the south rests New Mexico, to the southwest lies a sliver of Arizona, and to the west runs Utah.
The most famous of these junctions is the Four Corners Monument, the only spot in the United States where four state boundaries intersect at a single quadripoint (Colorado, Utah, New Mexico, and Arizona). Even this landmark carries a historical quirk: due to early measurement discrepancies, the physical monument sits slightly away from the exact mathematical intersection decreed by Congress. More details on regional demographics and physical boundaries can be found through the U.S. Census Bureau.
Frequently Asked Questions
Is Colorado legally considered a rectangle?
Legally and politically, Colorado is defined by its statutory boundaries set out by acts of Congress. Mathematically and cartographically, however, it is a complex polygon with 697 sides due to surveying inaccuracies and the curvature of the Earth.
Why are so many Western state borders straight lines?
Unlike Eastern states whose boundaries often follow rivers, mountain ridges, or colonial grants, Western territories were organized by the federal government using a grid system based on latitude and longitude. This system accelerated land sales, settlement, and statehood organization.
Does the northern border really measure shorter than the southern border?
Yes. Because meridians of longitude converge toward the North Pole, the northern edge of Colorado along the 41st parallel is roughly 22 miles shorter than the southern edge along the 37th parallel.
Can you see the border deviations without special equipment?
Most of the 697 individual border segments are tiny adjustments measuring only a few feet or yards. While you won't spot them easily from a car window, topographic maps and GIS overlays clearly highlight the jagged nature of these historical lines.
