Where the Yellowstone Met the Frontier:

The Brief, Turbulent History of Fort Pease

Introduction

Among the many military posts, trading stations, and river landings that appeared and disappeared during Montana’s territorial era, Fort Pease occupies an unusual place. It existed for only a short time, left few surviving physical traces, and was quickly overshadowed by larger and more durable institutions such as Fort Keogh. Yet during the critical years of 1875 and 1876, Fort Pease stood at the intersection of commerce, military strategy, Indigenous resistance, and the changing geography of the northern plains.

Located near the confluence of the Bighorn and Yellowstone rivers in present-day Treasure County, Montana, Fort Pease began not as a military installation but as a private commercial venture. Within a year, however, it became entangled in the Great Sioux War of 1876, served as a temporary base for United States Army operations, and witnessed events connected to the campaign that culminated in the Battle of the Little Bighorn. Its history illustrates how rapidly the northern plains were being transformed in the final decades of the nineteenth century.

Geography and Strategic Location

The site selected for Fort Pease lay a few miles below the mouth of the Bighorn River on the Yellowstone. For traders from the Gallatin Valley and Bozeman, the location appeared promising. Steamboat traffic on the Yellowstone had expanded after the Civil War, and entrepreneurs believed the confluence might become an important transfer point for goods moving between river transport and overland routes. Contemporary accounts describe the post as being situated near the earlier site of Fort Lisa, one of the fur-trade establishments that had operated in the region decades before.

The Yellowstone River functioned as one of the principal transportation corridors of the northern plains. Yet geography that seemed advantageous to traders also carried risks. The area occupied an important place within the hunting grounds used by Lakota Sioux and Northern Cheyenne peoples. The abundance of buffalo, game, timber, and river access made the region valuable long before Euro-American traders arrived. By the mid-1870s, increasing incursions by miners, traders, and military expeditions heightened tensions across the Yellowstone country.

Founding of the Trading Post

Fort Pease was established in June 1875 by a group of Gallatin Valley businessmen and traders. The post was named after Major Fellows D. Pease, a frontier trader and expedition leader who had been associated with commerce in the region. According to contemporary descriptions, the establishment consisted of log buildings enclosed by a cottonwood palisade, creating a fortified trading compound roughly two hundred feet square. The structure reflected the practical realities of frontier commerce: it was designed to store goods, house personnel, and provide a degree of protection in an isolated environment.

The investors hoped the fort would become the head of navigation on the Yellowstone and a commercial center linking the river trade with Montana’s interior settlements. Such ambitions were common during the territorial period. Many frontier communities and trading ventures were founded on expectations that transportation networks would shift in their favor. Some prospered; many did not.

From the outset, Fort Pease occupied contested ground. The post’s founders viewed the site as an economic opportunity, but Indigenous peoples saw yet another intrusion into lands they relied upon for hunting and travel. The resulting conflict would define the brief life of the fort.

Conflict on the Yellowstone

The winter of 1875–1876 proved difficult for those stationed at Fort Pease. Relations between the occupants and nearby Lakota bands deteriorated rapidly. Historical accounts indicate that the post experienced repeated harassment and attacks during the winter months. Several trappers associated with the establishment were killed, while others were wounded. The situation became increasingly precarious as supplies dwindled and fears of a larger assault grew.

These events occurred against the backdrop of a broader crisis. In late 1875, federal authorities issued ultimatums demanding that Lakota and Northern Cheyenne groups living outside reservation boundaries report to agencies by January 31, 1876. Many bands refused or were unable to comply. Federal officials subsequently classified them as hostile, setting the stage for a major military campaign. Across the northern plains, tensions escalated as the Army prepared operations designed to force Indigenous peoples onto reservations.

The difficulties at Fort Pease therefore reflected more than a local dispute. They formed part of a widening struggle over sovereignty, land use, and federal policy throughout the northern plains.

Military Intervention and Major Brisbin

By early 1876, conditions at the fort had become serious enough that appeals for military assistance were sent to Fort Ellis near Bozeman. In March, Major James S. Brisbin led elements of the 2nd Cavalry to the site. His arrival relieved the immediate pressure on the occupants, but the Army’s response differed from what many of the traders expected.

Rather than establishing a permanent military garrison, Brisbin was ordered to evacuate the civilians. The military leadership viewed the isolated trading post as difficult to defend and of uncertain strategic value. After only a brief stay, Brisbin escorted the traders and trappers away from Fort Pease. The fort itself was left standing.

Observers assumed that the abandoned structures would soon be destroyed. Instead, when subsequent military forces arrived, they found the post largely intact. This unexpected survival allowed Fort Pease to acquire a second life as a military outpost.

The Montana Column Arrives

In April 1876, Colonel John Gibbon’s Montana Column descended the Yellowstone as part of the Army’s coordinated campaign against the Lakota and Northern Cheyenne. Gibbon’s force had marched from western Montana and was one component of a three-pronged operation that also included columns under General Alfred Terry and General George Crook.

When Gibbon reached Fort Pease on April 19, he discovered the abandoned trading post still standing. Accounts from the expedition note that an American flag remained flying above the fort and that a dog greeted the soldiers upon arrival. The image is striking not because of its romance but because it underscores how abruptly the civilians had departed.

Gibbon occupied the site for approximately two weeks. During this period, scouting parties explored the surrounding country while the column awaited further instructions. The location provided shelter, storage, and a useful base from which to monitor movement along the Yellowstone and Bighorn corridors.

The occupation linked Fort Pease directly to one of the most studied military campaigns in western American history. Although overshadowed by later events, the fort briefly became part of the operational landscape that led to the Battle of the Little Bighorn.

Fort Pease and the Great Sioux War

The Army’s 1876 campaign sought to converge multiple columns on the large Indigenous encampments believed to be concentrated in the Bighorn region. Gibbon’s force advanced from the west, Terry and Custer approached from the east, and Crook moved northward from Wyoming Territory.

Fort Pease occupied a strategic position within this larger effort. Dispatches moved through the area, scouting operations originated there, and military planners considered its usefulness as a logistical support point. The site also became known as Terry’s Landing in some military references, reflecting its temporary role in the campaign.

Following the defeat of Lieutenant Colonel George A. Custer and much of the 7th Cavalry at the Little Bighorn in June 1876, surviving military forces regrouped. Gibbon’s command and elements of the battered 7th Cavalry subsequently utilized Fort Pease as a temporary base while awaiting reinforcements and supplies.

This period represented the high point of the fort’s military significance. For several weeks, the abandoned commercial venture became a staging ground for federal forces confronting one of the most consequential Indigenous victories of the nineteenth century.

Decline and Abandonment

Despite its temporary usefulness, Fort Pease faced practical limitations. The same river system that had inspired its founders’ commercial ambitions also restricted its long-term viability. Low water levels complicated steamboat supply operations, and military officials questioned whether the site could serve as an effective permanent post.

Army planners considered several alternatives for a new installation in southeastern Montana. Ultimately they selected a location at the confluence of the Tongue and Yellowstone rivers. Construction began in 1877 on what became Fort Keogh, a much larger and more strategically situated military post.

Once Fort Keogh entered service, Fort Pease lost whatever remaining value it possessed. The Army abandoned the site, and the structures eventually disappeared. Some accounts indicate that Lakota forces later burned the remaining buildings, though surviving evidence concerning the final destruction is limited. What is clear is that the fort ceased functioning within a remarkably short period after its establishment.

Legacy and Historical Significance

Fort Pease never developed into the commercial center envisioned by its founders. It did not become a major military installation, nor did it evolve into a lasting settlement. Yet its importance lies precisely in its brevity.

The fort reveals the fluid nature of the northern plains during the 1870s. Economic speculation, military expansion, Indigenous resistance, and environmental realities all converged at a single location. Within little more than a year, the site functioned as a trading post, a besieged frontier outpost, an abandoned compound, a military base, and finally a historical footnote.

Its story also highlights the limitations of frontier boosterism. Entrepreneurs imagined river commerce transforming the Yellowstone Valley, but geography, conflict, and shifting transportation patterns produced a different outcome. The region’s future would be shaped less by isolated trading forts than by military installations, railroads, ranching, and federal authority.

For historians, Fort Pease serves as a lens through which broader developments can be examined. The post illustrates how local events intersected with national policies toward Indigenous peoples and how individual commercial ventures became caught within larger struggles for control of the northern plains.

Today little remains at the original site. Historical markers and archival records preserve its memory, while scholars continue to place it within the larger narrative of Montana’s territorial era. Though overshadowed by the Little Bighorn, Fort Keogh, and other better-known landmarks, Fort Pease occupies a distinctive place in Montana history: a short-lived outpost whose existence coincided with a decisive turning point in the history of the Yellowstone Valley.

Works Cited

Brisbin, James S. “The Beef Bonanza; or, How to Get Rich on the Plains.” J. B. Lippincott, 1881.

Gibbon, John. John Gibbon Letter, 28 June 1876. Montana Historical Society Research Center Archives. ArchiveGrid, https://researchworks.oclc.org/archivegrid/archiveComponent/1530074710. Accessed 16 June 2026.

“Fort Pease.” Historical Marker Database, Custer Circle Project and City of Hysham, https://www.hmdb.org/m.asp?m=165326. Accessed 16 June 2026.

“Fort Pease, Montana.” Legends of America, https://www.legendsofamerica.com/fort-pease-montana/. Accessed 16 June 2026.

“FORT PEASE, April 23, 1876.” Rocky Mountain Husbandman, 11 May 1876. Library of Congress, Chronicling America Collection, https://tile.loc.gov/storage-services/service/ndnp/mthi/batch_mthi_jay_ver01/data/sn83025309/00294551864/1876051101/0222.pdf. Accessed 16 June 2026.

Malone, Michael P., Richard B. Roeder, and William L. Lang. Montana: A History of Two Centuries. Rev. ed., University of Washington Press, 1991.

“The March of the Montana Column.” Historical Marker Database, Montana Department of Transportation, https://www.hmdb.org/m.asp?m=190928. Accessed 16 June 2026.

Toole, K. Ross. Montana: An Uncommon Land. University of Oklahoma Press, 1959.

Utley, Robert M. The Lance and the Shield: The Life and Times of Sitting Bull. Henry Holt, 1993.