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Almon Thompson: The Self-Taught Cartographer Who Helped Found National Geographic

The thirty-three founders of the National Geographic Society were an adventurous and accomplished group. They included scientists, explorers, a journalist and a superintendent of the National Zoo. In recognition of the National Geographic Society’s recent 130th anniversary this series takes a look at their stories. By Mark Collins Jenkins Almon Thompson didn’t set out to...

The thirty-three founders of the National Geographic Society were an adventurous and accomplished group. They included scientists, explorers, a journalist and a superintendent of the National Zoo. In recognition of the National Geographic Society’s recent 130th anniversary this series takes a look at their stories.

By Mark Collins Jenkins

Almon Thompson didn’t set out to become an explorer.  When he began his career in 1864, after a brief stint as a soldier in the Civil War, it was as a school superintendent in Illinois.  It wasn’t until his brother-in-law, John Wesley Powell, began inviting him along on his expeditions to the Rocky Mountains that Thompson found his true calling. The early exploring parties Powell organized were makeshift, amateur affairs, which often included family members who acquired their expertise as they went.  This was how “Prof” Thompson, as he had become known, found himself enlisted as chief entomologist, and his wife, Powell’s sister, Nellie, as a botanist.

the Powell party, including almon Thompson, ready to start its journey, wyoming 1871.  Photograph by E.O. Beaman.


Professional obligations kept Thompson from accompanying Powell on his first famous exploration of the Grand Canyon and the Colorado River.  This expedition, which made his brother-in-law a national hero, resulted in Powell’s being given command of the Geographical Survey of the Rocky Mountain Region. The mission of the Powell Survey, as it was called, was to explore and map the Colorado River and the associated Colorado Plateau, that maze of canyon, mesa, butte, and gorge making up southern Utah and northern Arizona, country so difficult that it was the last unexplored area of the continental United States.  Powell brought his brother-in-law onboard as his chief topographical engineer, despite the fact that Thompson had no background in surveying. Nevertheless, “Prof” and Nellie headed west. He was 31 years old, and the greatest years of his life were about to begin.

Their first project was to run the Colorado River again, but slowly and carefully, mapping and charting along the way. Such a voyage would last many months, so they cached supplies along the route. When the team of about a dozen men stepped into three boats at Green River Station, Utah, in late May 1871, “Prof” was second in command. When four months later they pulled out for the winter at the mouth of the Paria River, over 200 miles downstream and 50 shy of the head of the Grand Canyon, Thompson was effectively in charge.

Almon Thompson at the Grand Canyon, 1872. Photograph courtesy USGS.

Major Powell was away much of the time, exploring the surrounding plateaus and studying the local Indians. But the expedition was in good hands: contrasted with his mercurial brother-in-law, Thompson was practical, levelheaded, and organized. In fact, he was mostly left on his own for a year, as Powell returned to Washington on Survey business.

That was the year Thompson passed from amateur to professional. The expedition wintered in the field, hoping to resume the river voyage in the spring. In the meantime, Thompson initiated the first mapping of the wild and canyon-strewn Colorado plateau. It was a daunting prospect, especially to someone teaching himself the difficult art of triangulation as he proceeded. By night he studied the glittering stars, seeking Polaris to anchor his baselines; by day he plunged into the juniper and pinon to draw them out. From the baselines, his topographers fanned out with chain and table, tools of the surveyor’s trade. Diligent and imperturbable, Thompson continued mapping, despite gold rushes, Indian scares, and other distractions, and gradually the last blank spot on the map began to shrink. He was, as one historian put it, “a man who liked to get things done.”

In 1873, after a year and a half of mapping, Thompson and his topographers completed the first comprehensive map of the Colorado Plateau and Grand Canyon.

In the process, he may have been the first white man to travel openly in the hostile Shivwit Indian country. He was also possibly the first white man to look into Bryce Canyon. He was certainly the first to explore the Henry Mountains, discovered by Powell in 1869 and shortly to make Grove Karl Gilbert one of geology’s immortals; and he discovered the Escalante, the last unmapped river left in the contiguous United States. In comparison, the completion of the boat trip through the Grand Canyon, accomplished in the summer 1872 despite perilously high water, seems almost anticlimactic.

Frederick Dellenbaugh, one of project’s topographers, would later recall Thompson’s achievement: “To his foresight, rare good judgment, ability to think out a plan to the last detail, fine nerve and absolute lack of any kind of foolishness, together with a wide knowledge and intelligence, this expedition”–and the scientific work of the entire Powell Survey, he added–“largely owe success.” Thompson himself, notably laconic, had merely said, “We done middling for greenhorns.”

It was a few years later when Thompson assumed what would become a pivotal role in founding the National Geographic Society. In fact, his is one of the six names who signed the original invitation soliciting those interested in forming a geographical society to convene at the Cosmos Club, along with Gardiner Greene Hubbard, A. W. Greely, John Russell Bartlett, Henry Mitchell, and Henry Gannett. At the resulting meeting, held on the evening of January 13th, 1888, it was Thompson who called the assembly to order.  Along with Powell and Clarence Dutton, he was one of the 15 “Incorporators,” those who subscribed the original Articles of Incorporation formally banding themselves together as a National Geographic Society. And at the new organization’s first formal meeting, he was elected one of five vice presidents, in charge of cartography, an office in which he served for several years. In a sense, “Prof” Thompson stands at the head of that cartographic tradition of which in later years the Society would become so proud.

Thompson remained in Washington for the remainder of his career. While his wife, Nellie, became a leading suffragette, he continued to work for the Geological Survey in ever more important administrative roles. In 1890, John Wesley Powell won Congressional permission for the U.S.G.S. to conduct an Irrigation Survey of the arid West as a preliminary to possibly reclassifying the lands opened for settlement. Powell entrusted that project’s most important facet, the topographical mapping of over 90% of the unmapped land of the public domain –virtually three-quarters of the West – to Thompson. But the Irrigation Survey – and Powell’s career at the Geological Survey – were destroyed by Congressional and special interest hostility. Nevertheless, Thompson continued his work at the U.S.G.S. Between 1896 and 1903, by which time he was 64 years old, he was in charge of all of its field and office work. He was also in charge of mounting exhibits, culminating in the Survey’s exhibit at the great 1904 Louisiana Purchase Exposition in St. Louis.

Almon Thompson died of stomach cancer on July 31, 1906, at the age of 67, and was buried in Arlington Cemetery, not far from the grave of John Wesley Powell. Dellenbaugh, the topographer and memoirist, could only write:

“Strew their graves with roses and forget them not. They did great work in solving the last geographical problem of the United States.”

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