Mapping Montana’s Last Unknown:

The Raynolds Expedition of 1859-1860 and the Federal Survey That Almost Found Yellowstone

Origins and Objectives

In the spring of 1859, the United States War Department confronted a conspicuous gap in its knowledge of the northern Rocky Mountain interior. Large portions of what are now Wyoming, Montana, and Idaho remained unmapped by any government expedition, known mainly through the oral accounts of fur trappers, Indigenous peoples, and a handful of traders who worked the upper Missouri and Yellowstone drainages. The Corps of Topographical Engineers, a specialized military branch that had directed western scientific exploration since 1838, was charged with filling that void. The result was the Raynolds Expedition of 1859 to 1860 — the final major government survey undertaken by the Corps before the Civil War dissolved it.

Captain William Franklin Raynolds, a forty-year-old West Point graduate with prior experience on the Great Lakes and northeastern boundary surveys, received his orders by telegraph in April 1859. The directive, issued by the War Department, instructed him to explore the region through which flowed the principal tributaries of the Yellowstone River and the mountains at the sources of the Gallatin and Madison forks of the Missouri. His mandate was comprehensive: he was to assess the numbers, habits, and disposition of the Indian nations in the region; its agricultural and mineralogical resources; its climate; the navigability of its rivers; and any topographical features that might facilitate or obstruct the construction of roads or railroads (Raynolds, Report on the Exploration of the Yellowstone River, 1868). The expedition was a tool of federal planning as much as scientific inquiry, aimed at laying the groundwork for what policymakers expected to be an eventual corridor of American settlement through the northern Rockies.

Raynolds was authorized to hire eight civilian assistants, provided with a budget of sixty thousand dollars, and promised a military escort of thirty infantrymen. He was also permitted to engage a guide. On the recommendation of the Chouteau Fur Company, long the institutional memory of the northern plains trade, Raynolds hired James Bridger — the celebrated mountain man and former trapper who had spent decades working the Rockies — at the rate of one hundred and twenty-five dollars per month (National Park Service, Bighorn Canyon, 2015). Bridger’s intimate familiarity with the country would prove indispensable, and at times his counsel would determine the course of the expedition as much as any order from Washington.

The Personnel and Departure

The party that assembled in early June 1859 was a carefully selected group of specialists. First Lieutenant Henry E. Maynadier of the Tenth Infantry served as Raynolds’s principal assistant and second-in-command. James D. Hutton served as topographer and official photographer. J. Hudson Snowden acted as a second topographer. Anton Schonborn — meteorologist and skilled artist — would produce some of the first visual representations of the Teton Range and Bighorn Canyon. Dr. M. C. Hines served as surgeon and assistant naturalist. The most scientifically consequential of the civilian staff was Dr. Ferdinand Vandeveer Hayden, a thirty-year-old naturalist, geologist, and physician who already possessed extensive field experience on the upper Missouri through his work with the Warren expeditions of 1856 and 1857 (Nottage, WyoHistory.org, 2023). Hayden’s presence on the Raynolds Expedition marked a turning point in his career: the observations he made in the region would eventually impel the post-war Hayden Survey, which produced the scientific basis for Yellowstone National Park.

The expedition officially departed St. Louis, Missouri, by steamboat on May 28, 1859, traveling up the Missouri River and pausing briefly at St. Joseph before continuing toward Fort Randall in present-day South Dakota, where thirty infantrymen under Lieutenant Caleb Smith joined the party. At Fort Pierre, Raynolds met with principal leaders of the Lakota Sioux — including Bear Rib of the Hunkpapas and Two Bears of the Yanktonais — distributing annuity goods and seeking passage through Lakota territory (Nottage, WyoHistory.org, 2023). The diplomatic gesture was practical as well as ceremonial: the expedition needed to move through country that was neither politically nor physically neutral.

Into Montana: The First Season

After departing Fort Pierre in late June, the expedition proceeded overland, skirting the Black Hills to the north before pushing into the Powder River basin. The terrain proved more obstructive than anticipated. Heavily laden supply wagons made the broken Powder River country nearly impassable, and Jim Bridger persuaded Raynolds to redirect the column toward the Yellowstone River instead (National Park Service, Bighorn Canyon, 2015). On this northern arc through what is now southeastern Montana, a significant, if largely unheralded, side trip occurred: topographer James Hutton, accompanied by the expedition’s Yanktonais-Sioux interpreter Zephyr Rencontre, located and documented the massive basalt column in northeastern Wyoming later known as Devils Tower — becoming the first documented white men to reach the base of that formation (Nottage, WyoHistory.org, 2023).

By late August the main party had reached the Yellowstone River in southern Montana. There the expedition encountered the Crow Nation — the Apsaalooke people for whom the Yellowstone and Bighorn valleys formed an ancestral homeland. Raynolds recorded his observations of Crow dress, horsemanship, and armament in his journal with a mixture of curiosity and the condescension typical of mid-century military writing. He noted that the Crow were well mounted and carried both firearms and bows, and that they bore a reputation as formidable fighters in the region (Raynolds, Report on the Exploration of the Yellowstone River, 1868). The Crow were not simply subjects of observation; they were a sovereign people with established territorial claims in the country through which Raynolds proposed to build roads. Raynolds appeared aware of this contradiction but did not dwell upon it in his official correspondence.

On September 2, 1859, Raynolds’s detachment reached the confluence of the Yellowstone and Bighorn rivers in south-central Montana, resupplying at Fort Sarpy — a fur trade post that Raynolds found in a state of disorder, its agent more interested in commerce with local Indians than in provisioning an Army expedition (National Park Service, Bighorn Canyon, 2015). Moving south from the Yellowstone, Raynolds led his group along the eastern flank of the Bighorn Mountains. On September 9, the expedition arrived at the mouth of Bighorn Canyon, where Raynolds halted to sketch and record geological observations. In his journal he described the canyon entrance as one of the most remarkable sights upon the continent, the river flowing out through reddish-tinted walls of perpendicular rock more than three hundred feet in height before meeting an impassable wall of rock (National Park Service, Bighorn Canyon Part 2, 2015). The party remained only a day before turning south and east toward Wyoming, skirting the Bighorn range until the two divisions of the expedition reunited at Deer Creek Station on the Platte River on October 12, 1859.

There, in winter quarters near what is now Glenrock, Wyoming, the party spent the cold months preparing for the following season’s push toward Yellowstone.

The Second Season and the Approach to Three Forks

On May 24, 1860, Raynolds and Maynadier again separated their forces at the junction of the Wind River and the Popo Agie River in Wyoming. Maynadier was directed to descend the Bighorn River and skirt the Absaroka Range, while Raynolds would lead the main body westward up the Wind River, attempting to cross the mountains at Togwotee Pass — a route Jim Bridger knew about — and then proceed north to reach the Three Forks of the Missouri in southwestern Montana (Baldwin, National Park Service, 2004). The plan called for the two divisions to reunite at Three Forks by the end of June in order to observe a total solar eclipse predicted for July 18, 1860 — an astronomically precise objective that added an unusual scientific urgency to the overland schedule.

The route proved impractical. Deep snow and a steep basaltic ridge barred the way at Togwotee Pass. Raynolds described the mountains as aesthetically magnificent but practically foreboding. With the eclipse observation deadline pressing, he abandoned the direct approach and turned to Bridger for an alternative. The veteran guide led the party south to Union Pass, allowing the expedition to cross the Continental Divide gap and descend through Jackson Hole, becoming among the first government parties to document that valley and the Teton Range. Schonborn produced sketches and Hutton attempted wet-plate photography of the Tetons, capturing images that would stand for years as the first formal visual records of the range (Nottage, WyoHistory.org, 2023).

Raynolds pressed north through present-day Idaho and into southwestern Montana, eventually reaching the Three Forks of the Missouri — the confluence of the Madison, Jefferson, and Gallatin rivers — in early July 1860. It was a site with deep historical resonance: Lewis and Clark had named the forks in 1805, and the junction was already understood by American geographers as a pivotal interior landmark. The Raynolds party had circumnavigated the Yellowstone plateau without entering it, both divisions of the expedition having encircled the future park region without penetrating its interior. Raynolds wrote candidly of having to content himself with listening to marvelous tales of burning plains, immense lakes, and boiling springs, without being able to verify those wonders (Baldwin, National Park Service, 2004).

In June 1860, the expedition crossed the Continental Divide at a low gap along the Madison River drainage in what is now Madison County, Montana — a pass Raynolds named Low Pass and which was subsequently renamed Raynolds Pass in his honor. Raynolds noted in his journal that it was so level that it was difficult to fix the exact point where the waters divided, describing it as one of the most remarkable and important features in the topography of the Rocky Mountains. The Historical Marker at the site records that Raynolds camped that night on the Madison River and regarded the pass as among the most significant topographic features of the entire Rocky Mountain chain (Historical Marker Database, Raynolds Pass, 2023). The two divisions reunited and the combined party returned down the Missouri, arriving in Omaha in October 1860.

Scientific Contributions and the Problem of Delay

The expedition generated a substantial body of data across multiple disciplines. Hayden conducted geological and natural history observations throughout both seasons, collecting fossil specimens including a new species of freshwater snail — later named Viviparus raynoldsanus in honor of the expedition leader — and producing systematic notes on the stratigraphy of the northern Rocky Mountain region. Hayden eventually published a formal Geological Report of the Exploration of the Yellowstone and Missouri Rivers in 1869, which built directly on his Raynolds fieldwork (Encyclopedia.com, Ferdinand Vandeveer Hayden, 2018). Schonborn’s meteorological records and the visual documentation produced the first formal records of Bighorn Canyon and the Teton Range for a government audience. The expedition’s topographers employed plane table methods for field sketching combined with odometer measurements and astronomical observations using sextants and barometers to compile precise locational data.

None of this material reached the public promptly. Raynolds returned to Washington in late 1860 and began preparing his report, but the secession crisis shattered his staff. The Civil War scattered his assistants, and Raynolds himself saw field service through the conflict. His comprehensive report — a document that would have been among the most important geographic syntheses of the northern Rockies — was not submitted until 1867 and not published by the Government Printing Office until 1868, nearly a decade after the expedition departed St. Louis (Raynolds, Report on the Exploration of the Yellowstone River, 1868). A map of the survey was published separately in 1864, driven by demand from emigrants heading to the Montana gold fields, but Raynolds’s substantive recommendations for wagon routes — including a prescient north-south corridor he believed would become the principal line of travel into the valley of the Three Forks — were unavailable before John Bozeman independently developed a trail along essentially the same alignment (Nottage, WyoHistory.org, 2023; WyoHistory.org, Bozeman Trail, 2014). The lag was not incidental: it meant that the expedition’s most actionable findings arrived too late to direct the first phase of Montana settlement.

A further limitation was the exclusion of Hutton’s photographs and the broader visual record from the final published report. Hutton's early field photography had suffered from poor chemical quality in the rugged backcountry, and the rich visual archive of Bighorn Canyon, the Teton Range, the Deer Creek winter quarters, and portrait studies of Indigenous people did not accompany Raynolds’s text in its 1868 edition. Hayden did successfully publish seven of the expedition’s photographs of Native people as lithographs in 1863, constituting the first field photographs of western Indians to be reproduced in that medium, but the broader artistic record remained largely inaccessible to the general public for generations (Nottage, WyoHistory.org, 2023).

Legacy and Historical Significance for Montana

The Raynolds Expedition is most often characterized by what it failed to accomplish: the discovery of Yellowstone. That framing, while understandable, obscures the expedition’s actual contributions to Montana history. The party was the first government scientific body to formally document the Crow in their Montana homeland during the expedition period, to produce systematic observations of the Bighorn River drainage, to record the geology and geography of the upper Yellowstone watershed, and to traverse the Continental Divide at what became Raynolds Pass in Madison County. In southwestern Montana, the party’s observations of the Madison River valley and the Three Forks area added precision to maps that had relied, since Lewis and Clark, on non-specialist accounts and the informal knowledge of the fur trade.

The expedition’s greatest Montana legacy may be indirect. Ferdinand Hayden’s experience in the Raynolds field seasons permanently fixed his scientific attention on the Yellowstone region. After the Civil War he returned to lead the government geological surveys of 1869 through 1872, producing the systematic scientific account of Yellowstone that persuaded Congress to establish the world’s first national park in 1872. Without the Raynolds Expedition’s reconnaissance — incomplete as it was — Hayden might not have had the preparation, the contacts, or the institutional confidence to mount those later campaigns (Encyclopedia.com, Ferdinand Vandeveer Hayden, 2018).

Raynolds’s observations on bison populations also merit attention in retrospect. Raynolds noted in his report the scale at which bison were being killed, raising concerns about the sustainability of hunting pressure at a time when most officials regarded the plains herds as inexhaustible. The observation was not unprecedented — earlier traders and missionaries had made similar remarks — but its inclusion in an official government document distinguished it from informal anecdote.

William Raynolds’s name survives on Montana’s landscape at Raynolds Pass along the Continental Divide in Madison County, and on Raynolds Peak in the Teton Range, named for him in 1938. Jim Bridger’s role in shaping the expedition’s routes through Montana — persuading Raynolds away from impassable terrain on multiple occasions and guiding the party through what are now some of the most historically significant passes in the northern Rockies — is a reminder that the formal explorer often depended on informal expertise that rarely appears in official records. The expedition that “failed” to find Yellowstone mapped an enormous swath of Montana country, helped lay the cartographic foundation for future settlement corridors, and trained the scientist who would eventually fulfill the promise its own circumstances denied.

Works Cited

Baldwin, Kenneth H. “Terra Incognita: The Raynolds Expedition of 1860.” Enchanted Enclosure: The Army Engineers and Yellowstone National Park. U.S. Army Corps of Engineers and National Park Service, 2004. National Park Service, https://www.nps.gov/parkhistory/online_books/baldwin/chap2.htm. Accessed 1 June 2026.

Encyclopedia.com. “Ferdinand Vandeveer Hayden.” Encyclopedia.com, 23 May 2018, https://www.encyclopedia.com/people/history/historians-miscellaneous-biographies/ferdinand-vandeveer-hayden. Accessed 1 June 2026.

Goetzmann, William H. Army Exploration in the American West, 1803-1863. Yale University Press, 1959.

Historical Marker Database. “Raynolds Pass Historical Marker.” HMDB.org, https://www.hmdb.org/m.asp?m=187603. Accessed 1 June 2026.

National Park Service. “Raynolds Expedition 1859-60 and Bighorn Canyon Part 1.” Bighorn Canyon National Recreation Area, U.S. Department of the Interior, 24 Feb. 2015, https://www.nps.gov/bica/learn/historyculture/raynolds-expedition-1859-60-and-bighorn-canyon-part-1.htm. Accessed 1 June 2026.

National Park Service. “Raynolds Expedition 1859-60 and Bighorn Canyon Part 2.” Bighorn Canyon National Recreation Area, U.S. Department of the Interior, 24 Feb. 2015, https://www.nps.gov/bica/learn/historyculture/raynolds-expedition-1859-60-and-bighorn-canyon-part-2.htm. Accessed 1 June 2026.

Nottage, James H. “Rivers, Mountains and Plains: The Raynolds Expedition of 1859-1860.” WyoHistory.org, Wyoming State Historical Society, 31 May 2023, https://www.wyohistory.org/encyclopedia/rivers-mountains-and-plains-raynolds-expedition-1859-1860. Accessed 1 June 2026.

Nottage, James H. “A Brief History of the Bozeman Trail.” WyoHistory.org, Wyoming State Historical Society, 20 Nov. 2014, https://www.wyohistory.org/encyclopedia/brief-history-bozeman-trail. Accessed 1 June 2026.

Raynolds, William F. Report on the Exploration of the Yellowstone River. Government Printing Office, 1868. HathiTrust Digital Library, https://babel.hathitrust.org/cgi/pt?id=mdp.39015011349597&view=1up&seq=7. Accessed 1 June 2026.

Raynolds, William F., edited by Marlene Deahl Merrill and Daniel D. Merrill. Up the Winds and Over the Tetons: Journal Entries and Images from the 1860 Raynolds Expedition. University of New Mexico Press, 2012.