A Tour of the Big 13 Photos and information on the world's giant natural arches by David Brandt-Erichsen and Jay Wilbur

Introduction

On this page the Natural Arch and Bridge Society (NABS) lists all the natural arches in the world we know about that have spans greater than 200 feet. Placement on this list is based on the best data currently available to us and is subject to change pending more accurate measurements. Indeed, the ranking on this page has changed ten times since this page was first created, and further changes are anticipated in the future, especially because we currently have less accurate data for the arches that are outside the United States.

To accurately compare the sizes of natural arches, two things are needed: (1) agreement on just what points to measure, and (2) accurate measurements from those agreed-upon points. Without agreement on what points to measure, different people taking measurements may get very different results no matter how accurately the measurements are taken.

In the table below, ranking is based solely on the criterion of greatest span, where span is a dimension defined so that arches of different geometries can be consistently and accurately compared (see below for further explanation). The web pages indexed by the table below include photographs and information about each of these giant arches. You can directly link to each arch, or page through them sequentially.

The natural arches with spans greater than 200 feet are:

Rank	Image	Name	Location	Span
1 (?)		Fairy Bridge	Buliu River, Guangxi, China	~295 ft
2		Landscape Arch	Arches National Park, Utah	290 ft
3		Kolob Arch	Zion National Park, Utah	287 ft
4		Aloba Arch	Ennedi Range, Chad (Sahara Desert)	~250 ft
5		Morning Glory Natural Bridge	Moab, Utah	243 ft
6		Rainbow Bridge	Rainbow Bridge National Monument, Utah	234 ft
7		Gaotun Natural Bridge	Bazhou He Scenic Area, Guizhou, China	~230 ft
8		Sipapu Natural Bridge	Natural Bridges National Monument, Utah	225 ft
9		Stevens Arch	Escalante River, Utah	220 ft
10-11		Shiptons Arch (Tushuk Tash)	Near Kashgar, Xinjiang, China	~212 ft
10-11		Jiangzhou Arch	Jiangzhou, Guangxi, China	~212 ft
12		Outlaw Arch	Dinosaur National Monument, Colorado	206 ft
13		Snake Bridge	Sanostee, New Mexico	204 ft

Table last revised May 20, 2009

More Details and Notes

Readers should note that this is not a list of the "largest" natural arches for the simple reason that there is no precise definition of "largest" that would apply to the many different geometries displayed by natural arches. What criteria would you use for "largest" — width, height, area, volume? (The latter two would be very impractical to measure as well as difficult to precisely define.) And at exactly what points would you take the measurements?

To attempt to answer these questions, the Natural Arch and Bridge Society assembled a working group of experts (inlcuding geologists, physical geographers, a physicist, and a mathematician) to come up with a set of standards and definitions for measuring natural arches. The results (some are quite technical) can be found in our Arch Info pages. No other system currently exists that permits consistent and accurate comparison of the sizes of natural arches.

For our purposes here, a less technical (and less precise) definition of the span of an arch is the horizontal extent of unsupported rock. The two illustrations below will help in understanding just what this means.

Illustration courtesy Utah Geological Survey

In the illustration above, the span would be the sum of the horizontal lines A and A'. Since this arch is not symmetrical, the span cannot be measured directly in a single line. Measuring B or C would produce quite different results.

The illustration above shows a three-dimensional view of an arch in which the dimensions differ considerably between the "front" and the "back" of the arch, which can result in wide discrepancies in reported spans. In this case, the NABS-defined span would be the maximum horzontal dimension of the most constrained part of the opening, as shown. This difference may account for a reported span for Gaotun Natural Bridge at 450 feet whereas NABS estimates the span at 230 feet. The advantage of the NABS system of measurement is that it can be applied to arches of any geometry and will always produce consistent results. For more information, see the article on Finding the Span of Arches with Simple Shapes.

It remains uncertain which arch has the greatest span in the world. For many years the only two known contenders for this position were Landscape Arch in Arches National Park and Kolob Arch in Zion National Park. The most precise measurement of Landscape Arch was obtained in 2004, and the most precise measurement of Kolob Arch was obtained in 2006, finally establishing Landscape Arch as having the greater span (by a mere three feet). Fairy Bridge in China, however, may have an even greater span than Landscape Arch. Our best estimate currently puts it in first place by a small margin, but this estimate is based solely on photoanalysis and we are anxious to obtain a more precise measurement.

Whereas no arch is currently confirmed to exceed 300 feet in length, there were two arches, now fallen, which may have exceeded 300 feet. These are Bridge of the Gods in the Columbia River Gorge of Oregon-Washington, and Fallen Monarch in Natural Bridges National Monument, Utah.

Here are some of the major changes to this page since it was first created:

• 2004: Aloba Arch measured and confirmed to be over 200 feet.
• 2006: Outlaw Arch discovered.
• 2007: Kachina Natural Bridge removed from list when a precision laser measurement found that it was less than 200 feet.
• 2009: Wrather Arch removed from list when a new measurement showed the span was less than 200 feet.
• 2009: Information obtained on four natural arches in China that are over 200 feet.

Now start your Big 13 Tour with a trip
to our first giant, Fairy Bridge...