When greed won at the Missouri River and wiped out 90% of the Mandan nation

Captain Pratt’s Deadly Voyage to Fort Clark

The steamboat St. Peters docked at Fort Clark in June 1837 with a dark secret.

Captain Bernard Pratt knew smallpox had spread on his ship but still pushed up the Missouri River to trade. At the fort, now near Washburn, North Dakota, some 2,000 Mandan people lived in earth lodges.

Despite warnings to stay back, they came to trade and celebrate. Within weeks, the virus tore through their villages.

By October, only 138 Mandan lived. Their great chief Mato-Tope died cursing the white traders who brought this death.

Fort Clark stands today as a stark reminder of how greed wiped out an entire way of life in just four months.

The Deadly Voyage Begins on the St. Peters

The American Fur Company sent its new steamboat St. Peters up the Missouri River in spring 1837.

The 119-ton boat carried trade goods for Native American tribes along the river. Captain Bernard Pratt led this normal trading trip that soon turned deadly.

Before reaching Fort Leavenworth on April 29, a deckhand got a fever. At Black Snake Hills, three Arikara women boarded the boat to go home.

They also carried smallpox.

Warning Signs Ignored by Profit-Hungry Captain

When the St. Peters stopped at Fort Leavenworth, the sick deckhand clearly had smallpox.

Crew members asked Captain Pratt to leave the sick man behind and wait. Pratt said no.

The company had a schedule and money to make. The three Arikara women also got smallpox during the trip upriver.

Pratt kept going anyway, choosing his delivery schedule over stopping a disease that could kill entire communities.

Steamboat Pulls into Fort Clark Despite Danger

The St. Peters reached Fort Clark near today’s Washburn, North Dakota at 3 p.m. on June 19, 1837.

About 2,000 Mandan, Hidatsa, and Arikara people lived in earth houses nearby.

Fort Clark boss Francis Chardon heard about the sickness on board and tried to warn the Native Americans to stay away. No one listened.

The yearly trading party was too important. Tribes gathered around the boat, not knowing about the killer that just arrived.

Trading Celebration Turns into Death Sentence

Workers unloaded goods and loaded furs while people sang and danced on June 19-20. The sick Arikara women left the boat to join their people living with the Mandans.

Native Americans packed the dock, happy to get trade goods and government money. No one knew that deadly smallpox spread between them with each contact.

The St. Peters finished its work and left on June 20, going upstream to Fort Union, leaving death behind.

Smallpox Claims Its First Victim

Fort Clark boss Francis Chardon wrote in his journal on July 14, 1837: “A young Mandan died today of the Small Pox. ” This marked the first recorded death in what became a terrible outbreak.

The sickness spread fast through the crowded earth houses where families lived close together. Deaths grew from 5-6 daily to 10-15 men per day.

Chardon soon stopped counting women and children deaths as the numbers got too big.

Beloved Chief Four Bears Makes His Final Speech

Mato-tope, known to white traders as Four Bears, died on July 30, 1837.

Famous artists George Catlin and Karl Bodmer painted this respected Mandan chief as a symbol of his people’s proud culture.

Before dying, Four Bears gave a last speech calling white men his people’s worst enemies for bringing “death to all my tribe. ” The loss of this loved leader crushed the spirits of the already suffering Mandan people.

Tribe Members Choose Death Over Suffering

Some Mandans killed themselves rather than face the “rotting death” from smallpox. With bodies covered in painful sores, victims suffered badly before dying.

Survivors blamed the traders for bringing the sickness and tried to kill Chardon. The boss kept armed guards but couldn’t protect his own family.

His youngest son died in the outbreak.

Traditional Mandan culture fell apart as spiritual leaders, family heads, and medicine men died one after another.

Bodies Overwhelm Burial Capacity

Chardon wrote on August 11: “they die so fast that it is impossible” to keep count. Bodies piled up faster than survivors could bury them.

People put some in mass graves, while others went into the Missouri River. The smell from Fort Clark carried 300 yards away.

In some villages, 800 people died with only 14 survivors. The once-busy Mandan communities became ghost towns filled with rotting bodies.

Medical Attempts Make Things Worse

Fort Union tried basic shots using infected pus from Jacob Halsey, a clerk who got smallpox. They gave shots to thirty Indian women, but the results proved “absolutely devastating.”

Without proper medical knowledge, these makeshift efforts spread the disease more instead of stopping it.

Several St. Peters deckhands died before the boat even reached Fort Union, showing how deadly this type of smallpox was.

Disease Spreads Across the Plains

Smallpox moved upstream to the Blackfeet, killing about two-thirds of their tribe. By 1840, half the Assiniboine and Arikara people had died.

One-third of the Crow and a quarter of the Pawnee died too. More than 17,000 Native Americans died along the Missouri River alone.

Sadly, Plains tribes didn’t get a federal shot program in 1832 that might have stopped this disaster.

Survivors Form a New Nation From the Ashes

By October 1837, only 138 of the original 2,000 Mandans remained alive. Some accounts put the number as low as 27 survivors.

The Hidatsa lost half their population, while the Arikara lost two-thirds.

The devastated survivors eventually joined together at Like-a-Fishook village, forming what became known as the Three Affiliated Tribes.

The once-powerful Mandan nation, with its rich cultural traditions and political influence on the northern plains, was forever altered by a single steamboat’s deadly cargo.

Visiting North Dakota Heritage Center, North Dakota

The North Dakota Heritage Center at 612 East Boulevard Avenue in Bismarck offers free admission to learn about the devastating 1837 smallpox outbreak that killed 90 percent of the Mandan people.

You can see Karl Bodmer’s 1830s paintings of Upper Missouri River Native life and visit the Innovation Gallery with Mandan language greetings.

The museum is open Monday-Friday 8am-5pm and weekends 10am-5pm. Grab dinosaur cookies at James River Café or browse North Dakota merchandise at the Museum Store.

This article was created with AI assistance and human editing.

Read more from this brand:

• Catastrophe on the Missouri: the Mandan smallpox epidemic of 1781-1782
• The 800-year-old North Dakota village that traded across half of America
• Sacagawea: from kidnapped Shoshone child to Lewis and Clark’s cherished guide