Wyoming Trading Post History: Forts, Furs, and Five Trails

Between 1834 and 1868, Wyoming held more consequential trading posts than any comparable stretch of the American West. Fort William became Fort Laramie, the most important post on the Northern Plains. Fort Bridger resupplied the wagon trains. Smaller posts worked the river crossings and stage roads. This guide covers all of them: who built them, what they traded, how they died, and where to stand on the ground they occupied.

The reason so much of this history happened in one place is not luck. It is a gap in a mountain range.

Why Wyoming: the geography that built the posts

The Rocky Mountains run like a wall from Canada to New Mexico, and for a wagon there is essentially one good door: South Pass, a broad sagebrush saddle over the Continental Divide in west-central Wyoming. The grade is so gentle that emigrants sometimes asked their guides when the crossing would happen, not realizing it already had.

That one door concentrated the entire overland migration. The Oregon Trail, the California Trail, and the Mormon Trail all ran the same corridor up the North Platte, along the Sweetwater, and over South Pass. The Pony Express followed in 1860. The Overland Trail cut across southern Wyoming in 1862. The Bozeman Trail split north toward Montana gold in 1863. Six named routes, one state, and every one of them needed supply points.

A trading post is a simple business: put goods where people run out of them. Nobody in North America ran out of more things in more predictable places than a Wyoming-bound traveler in the 1840s and 1850s. The posts went up exactly where the need peaked, at river crossings, trail junctions, and the last grass before hard country.

For the broader story of what these posts were and how the model worked from Hudson Bay to the Southwest, start with our companion piece, what a trading post actually was. This guide stays in Wyoming.

Before the posts: the rendezvous (1825-1840)

Wyoming’s first trading system had no buildings at all.

In 1825, William Ashley, a Missouri businessman who had sent trapping brigades into the Rockies, tried an experiment. Instead of requiring trappers to haul furs back to St. Louis, he hauled the store to the trappers. His instructions set “the place of randavoze” on the Green River for July. It worked so well it ran for fifteen more years.

The rendezvous was a two-week summer market: supply caravans came west loaded with traps, powder, blankets, coffee, sugar, and whiskey, and went east loaded with beaver. Most rendezvous met in the Green River valley of southwestern Wyoming. Six of the last eight were held near the junction of Horse Creek and the Green River, west of present-day Pinedale, with other Wyoming sites near McKinnon, Granger, Lander, and Riverton.

The economics were brutal and everyone involved knew it. In 1834, the Boston merchant Nathaniel Wyeth signed an agreement to deliver $3,000 worth of trade goods at the next rendezvous, then arrived to find the trappers had already bought from a rival caravan. Goods at rendezvous sold at mountain prices, several times their St. Louis cost, because the freight was 800 miles of prairie, river, and hostile ground. The trapper Osborne Russell, who worked these mountains from 1834 to 1843, left the best first-person record of the era in his Journal of a Trapper, still in print and still the book to read if you want the rendezvous from the inside.

Two things killed the rendezvous. Fashion in London and Paris shifted from felt hats to silk in the mid-1830s, and the beaver itself was nearly trapped out. The last rendezvous met on the Green in 1840. By then a different model was already standing on the Laramie River: walls, a gate, and year-round inventory.

Fort Laramie: the post that outlived everything (1834-1890)

On May 31, 1834, a party working for the fur traders William Sublette and Robert Campbell laid the foundation log of a cottonwood stockade where the Laramie River meets the North Platte. One of the men recorded it in his diary that day: “This day we laid the foundation log of a fort, on Laramee’s fork.” They called it Fort William.

The location was close to perfect. It sat on the buffalo-robe country of the Lakota, Cheyenne, and Arapaho, near the natural road west, with timber and water. Fort Bonneville, built two years earlier near the Green, had been abandoned so fast the trappers called it Fort Nonsense. Fort William held, and became the first permanent trading post in Wyoming.

It changed hands fast in the way fur trade property did. Sublette and Campbell sold in 1835 to Fontenelle, Fitzpatrick & Co. A year later it passed to Pierre Chouteau and the American Fur Company, the dominant fur operation in the country. By 1841 the cottonwood stockade was rotting, so the company spent $10,000 on a whitewashed adobe replacement and named it Fort John after a company partner. Nobody used the name. Travelers called it Fort Laramie, after the river, which carried the name of a French trapper killed in the area years before.

Through the 1840s the fort’s business pivoted from beaver to buffalo robes, and then to something the founders never planned: emigrants. Fort Laramie sat a third of the way to Oregon, right where wagon trains needed flour, repairs, and fresh animals after the first 600 miles. By the late 1840s the wagon traffic was the business.

The U.S. government noticed the same thing. In June 1849, the Army purchased Fort Laramie from the American Fur Company for $4,000, and the Regiment of Mounted Rifles made it a military post. For the next 41 years it was the Army’s anchor on the Northern Plains: staging ground, supply depot, and the site of the great treaty councils of 1851, 1866, and 1868. The 1868 council ended Red Cloud’s War, the only war the United States lost outright to an Indian nation, and the treaty signed at the fort ceded the Powder River country back to the Lakota for eight years.

The Army closed Fort Laramie in 1890, the same year the frontier officially closed. The standard history of the post, fifty-six years of trade, treaties, and garrison life in one volume, is Hafen and Young’s Fort Laramie and the Pageant of the West, 1834-1890.

Fort Bridger: the mountain man opens a store (1843)

By 1840 Jim Bridger had spent two decades as a trapper, guide, and partisan, and could read the market as well as any man alive. The beaver trade was dead. The wagon trade was beginning. In 1843 he and his partner Louis Vasquez built a post on Blacks Fork of the Green River in southwestern Wyoming: two rough double-log houses about 40 feet long, joined by a horse pen, with a blacksmith shop.

The plan, in Bridger’s own framing, was to serve two markets at once: the Shoshone and other tribes he had traded with for years, and the Oregon- and California-bound emigrants who would arrive broke-down and short of everything after crossing South Pass. The blacksmith shop was the tell. Emigrants did not need beaver traps. They needed tires reset, oxen shod, and axles replaced, and Bridger put the forge in from day one.

Then the neighborhood changed. The Mormon Pioneer Company passed through on July 7, 1847, on the way to the Salt Lake Valley, and within a few years Brigham Young’s settlements considered Bridger Valley their hinterland. Relations soured; Mormon authorities accused Bridger of selling liquor and ammunition to the tribes. In 1853 Young sent the militia for him, and Bridger fled before they arrived. The Mormons walled the fort in stone, built Fort Supply nearby, and ran the valley until 1857, when the Utah War brought a U.S. Army column under Albert Sidney Johnston. Rather than hand over the forts, Mormon militia burned both. The Army rebuilt Fort Bridger in 1858 and garrisoned it, with one gap, until 1890.

So the same post was, in sequence: a mountain man’s store, a Mormon outpost, a war casualty, and an Army fort. No other building in Wyoming compresses the territory’s whole story like that. The full account is Fred Gowans’ Fort Bridger: Island in the Wilderness, the standard work on the post.

The crossing posts: ferries, bridges, and Fort Caspar

Not every post guarded a junction. Some guarded a river.

The North Platte crossing near present-day Casper was one of the worst moments of the emigrant road. Brigham Young’s company established a ferry there in 1847, and ferrying emigrants became a profitable seasonal business. In the late 1850s the trader Louis Guinard built a toll bridge at the site, with a trading post alongside, on the logic that a man who has just been told the bridge costs several dollars is standing right next to your store.

The military arrived for the telegraph. Platte Bridge Station was established in 1862 to protect the transcontinental telegraph line and mail route. On July 26, 1865, Cheyenne forces under Roman Nose and Lakota under Red Cloud attacked an Army detachment escorting a supply train near the bridge. Twenty-six soldiers died, among them Lt. Caspar Collins, and the expanded post was renamed in his honor, with his first name misspelled as Casper for decades until the site’s name was corrected. The city kept the misspelling.

Fort Caspar’s end previews the end of every Wyoming post: the Union Pacific Railroad built through southern Wyoming, the telegraph moved to the rail line, and the fort lost its reason to exist. The Army dismantled the buildings and hauled the materials to Fort Fetterman.

The stage road posts: Fort Halleck and the Overland years

In 1862, constant raids pushed the mail and stage traffic off the North Platte road to a southern route, the Overland Trail, and the stage king Ben Holladay built 17 stations across southern Wyoming for daily coach and mail service. To guard them, the Army built Fort Halleck at the north end of Elk Mountain, the only military post in the 350 miles between Camp Collins in Colorado and Fort Bridger.

The traffic it protected was staggering for a road this remote: in 1864 alone, more than 4,200 wagons carrying 17,584 emigrants and over 50,000 animals passed the fort. Fort Halleck lasted exactly as long as the road mattered. The Union Pacific surveyors came through, the railroad’s path was set, and the fort was decommissioned on July 4, 1866, its buildings dismantled and hauled east to build Fort Sanders near Laramie.

If you want a single sentence for what happened to Wyoming’s posts between 1866 and 1869, that is it: the railroad did not defeat them, it absorbed them, lumber and all.

What the posts traded, and what it cost

The inventory of a Wyoming trading post barely changed for thirty years; only the customer changed.

In the fur years the inbound goods were the classic trade list. When Nathaniel Wyeth freighted his $3,000 consignment toward the 1834 rendezvous, it held beaver traps, pots, pans, awls, axes, needles, knives, guns, cloth, beads, and mirrors, plus the luxuries: coffee, sugar, whiskey, and ribbons. Out the other side of the counter went beaver pelts, and as beaver faded, buffalo robes by the tens of thousands, the warm winter robes that heated sleighs and carriages across the eastern states.

In the emigrant years the same shelves turned over to flour, bacon, dried fruit, coffee, sugar, gunpowder, rope, and wagon hardware, plus the two services no traveler could pack: the forge and the fresh ox. A wagon family that had broken an axle west of Fort Laramie did not negotiate hard on price, and the posts knew it. Mountain prices were the rule from the first rendezvous to the last toll bridge.

Three things on that list have not left the trail. Wool blankets were the single most demanded trade good of the fur era, graded and priced by point marks woven into the edge; a Pendleton wool blanket is the direct descendant of that trade, and Pendleton’s national park designs began as trade-blanket patterns. Coffee boiled over an open fire came west in the same panniers, and an enamelware camp set or a graniteware percolator is the same technology the later posts stocked once enameled steel replaced tin. And every pannier, pack, and wagon cover on the road was held down with the ancestor of a plain cotton lash rope. None of this gear has needed reinventing. That is roughly the founding idea of this site.

For what the trappers themselves carried on their belts, see our piece on the possibles bag, and for the working vocabulary of the era, the heritage gear glossary covers manty, latigo, point blanket, and seventy-some other terms.

The end of the post era

Mark the death of the Wyoming trading post at 1869, when the Union Pacific’s rails crossed the state and the golden spike went in at Promontory. The logic of the post, goods cached at the hard points of a slow road, collapsed when the road got fast. A transcontinental emigrant of 1870 rode through Wyoming in days, not months, and bought supplies from a railroad town storefront in Cheyenne, Laramie, Rawlins, or Evanston, towns the railroad invented as it went.

The posts themselves went three ways. The Army kept the useful ones as forts through the Indian Wars, then closed those too; Fort Laramie and Fort Bridger both shut in 1890. The redundant ones were dismantled for lumber, like Fort Halleck and Fort Caspar. And a few sites just emptied out, the same way the gold camps emptied when the veins quit.

What survived was the model. The general store, the ranch supply, the co-op, every one of them runs the trading post playbook: put the goods where people run out of them, take payment in whatever the country produces, and keep a forge or its modern equivalent out back. The name survived too, on businesses across the West, including the one whose journal you are reading.

Visiting the posts today

All three major sites are preserved, and all three are worth the drive. They are spread across the state, so plan them as stops on a larger loop rather than one trip.

Fort Laramie National Historic Site sits three miles off US 26 near the town of Fort Laramie, in the southeast corner of the state. This is the essential stop. The parade ground keeps original buildings from the military era, including Old Bedlam, the 1849 officers’ quarters that is the oldest standing building in Wyoming. The National Park Service runs it; grounds are open dawn to dusk and admission has historically been free, but verify current hours at nps.gov/fola before you drive.

Fort Bridger State Historic Site is in Bridger Valley off I-80 in the southwest corner, an easy stop on any Salt Lake-bound drive. The site has operated as a museum since 1933 and includes a reconstruction of Bridger and Vasquez’s original trading post alongside the later military buildings. Labor Day weekend brings the Fort Bridger Rendezvous, one of the largest mountain man reenactments in the country.

Fort Caspar Museum in Casper rebuilt the post and a section of Guinard’s bridge in 1936, with WPA labor, on the original site. It pairs naturally with Casper’s National Historic Trails Interpretive Center, which covers the emigrant road the post served.

The Museum of the Mountain Man in Pinedale covers the rendezvous era, and the actual Horse Creek rendezvous grounds lie a few miles west near Daniel. Pinedale’s Green River Rendezvous Days reenactment runs each July, in sight of the country where the original meetings happened.

If the trail history grabs you harder than the forts do, the most readable modern account of the road itself is Rinker Buck’s The Oregon Trail: A New American Journey, written after the author drove the whole trail, including the Wyoming stretch past every site in this guide, in a mule-drawn wagon in 2011.

Further reading

• Fort Laramie and the Pageant of the West, 1834-1890 by LeRoy R. Hafen and Francis Marion Young (1938; Bison Books). The standard history of the most important post on the Northern Plains.
• Osborne Russell’s Journal of a Trapper edited by Aubrey L. Haines (University of Nebraska Press). The best first-person account of the Wyoming fur trade, 1834-1843, by a man who lived it.
• The American Fur Trade of the Far West by Hiram Martin Chittenden (1902; Bison Books, two volumes). Still the foundational reference on the business side of the trade, written by an Army engineer who interviewed survivors of the era.
• Fort Bridger: Island in the Wilderness by Fred R. Gowans and Eugene E. Campbell (Brigham Young University Press, 1975). The standard work on Bridger’s post through its trading, Mormon, and military lives. Out of print; the link reaches used copies.
• The Oregon Trail: A New American Journey by Rinker Buck (Simon & Schuster, 2015). The emigrant road retraced by wagon, with the Wyoming posts as supporting characters.
• WyoHistory.org, the Wyoming State Historical Society’s encyclopedia, has deep entries on every post in this guide, free at wyohistory.org.