Like most people uprooted by the Cherokee Trail of Tears, Eliza Whitmire experienced terrible trauma.

In 1830, the U.S. government passed the Indian Removal Act. Eliza was about five years old when more than 3,000 armed militia arrived in Cherokee country in 1838. The militia companies forced her, her family and her community to march more than 1,000 miles west—through Northern Georgia, across the Ohio and Mississippi Rivers, to present-day Oklahoma.

Her mother described “the bitter memory” of “women and children…driven from their homes, sometimes with blows.” The sick, young and elderly sometimes rode in wagons, but the majority of the tens of thousands being displaced traversed the rugged territory on foot. Along the way, starvation posed a constant threat. It was a “time filled with horror and suffering for the unfortunate Cherokee and their slaves,” Eliza later recalled.

She and her family were among those enslaved people. Their removal story differs slightly from traditional Trail of Tears narratives because they were of African descent, enslaved and forcibly removed along with their Cherokee owners.

Eliza Whitmire’s story highlights the underreported complexities of slavery and the American frontier. Few historical narratives, for example, tell the story of a Georgia plantation owned and operated by Cherokee enslavers. And few chronicles of the frontier account for its human diversity. Often depicted as territory “discovered” and “tamed” by heroic white men, the frontier was, in many ways, America’s first melting pot. It was a place where indigenous people, and those of European, African and Mexican descent came into contact and tried to sort out their roles. And it was, for many who came there, a place shaped more by slavery than by freedom or opportunity.

To understand the story of enslavement in the West is to understand the history of land acquisition, cotton production and gold fever. Leaving coastal states in search of farmable land and natural resources, settlers pushed their way west—and once they crossed the Mississippi River—into newly acquired Louisiana and later Texas. The fever of Manifest Destiny, a term coined in 1845 by American journalist John O’ Sullivan, justified territorial expansion. White settlers believed it was their duty and right to conquer the land from the Atlantic to the Pacific, to spread their democratic ideals and “civilized” ways.

Sometimes, husbands went first to secure a place, and then sent for wives and children. Other families traveled together to the West. Many brought their enslaved laborers, pushing slavery into new regions and breathing new life into an institution that had been increasingly under legislative and moral attack. While ephemeral records make an accurate count impossible, historians estimate that close to 200,000 slaves traveled and worked the American frontier between 1830 and 1860.

One such migrant family was George Paschal and his wife, Sarah Ridge, whose story underscores the diversity of Western settlers—and their dependence on slavery. Sarah was the daughter of Cherokee leader Major Ridge, a wealthy slaveholder in the Cherokee Nation in Georgia before Indian Removal. Paschal came to Georgia with a voluntary militia sent to enforce Cherokee removal. They married, and by 1838, settled in Van Buren, Arkansas, where he worked as an attorney.

By the 1840s, however, enticed by his brother’s claims that Texas was the land of opportunity, the couple moved their growing family and their slaves to Galveston. In 1850, Ridge and Paschal divorced, with Ridge retaining their house in Galveston and their 12 slaves. By the mid-1850s, she moved her family to Chambers County, Texas in the southeastern part of the state, remarried a man 20 years her junior and set up a thriving cattle ranch dependent on enslaved labor. Paschal moved to Austin and became known for his opposition to Texas secession and to its siding with the Confederacy during the Civil War.

Like settlers, explorers of the American West also brought enslaved people to the frontier. Perhaps the most famous examples: York and Sacagawea, who journeyed across the continent as part of the Lewis & Clark expedition. In 1803, when President Thomas Jefferson authorized the Louisiana Purchase from France, and the new nation doubled in size, he asked Meriwether Lewis and William Clark to study the landscape, assess its economic potential and scout a passage to the Pacific coast.

Like many enslaved people brought along on journeys west, York provided invaluable support for Lewis and Clark’s expedition. Accounts from expedition reports and Clark’s letters reveal that York served as a scout, assisted in cooking, hauled supplies and helped construct shelters and forts. And unlike most in bondage, he was permitted to handle a gun and hunt.

Another valuable enslaved person on the expedition was Sacagawea, a Shoshone woman sold into marriage to a French trader. Her knowledge and understanding of the environment helped the expedition navigate unfamiliar territory and avoid starvation during the harsh Rocky Mountain winter. And her skills as an interpreter helped ease the explorers’ interactions with native groups they encountered. Not only did she facilitate communication, but her presence in the exploring party no doubt helped Lewis and Clark avoid armed conflict with the Native peoples in the region, since Native women rarely accompanied Plains Indian war parties.

Perhaps no other region in the West illustrates the dichotomy between opportunity and bondage more than California. In 1848, “gold rush fever” swept the region when gold nuggets were found at Sutter’s Mill. Thousands of people, enslaved and free, flooded the region, hoping to strike it rich.

Generally, owners severely limited their slaves’ mobility or handling of money. But for some, the enticement of easy riches loosened those strictures. William Campbell, for one, a white man who lived in Indian Territory, sent his slave, Green, to California with instructions to bring back 1,200 dollars’ worth of gold. Perhaps because he sent Green along with his brother-in-law and a diverse group of men, Campbell might have thought Green would be less likely to escape.

But to Green, freedom was more precious than gold. Much to Campbell’s dismay, he found his opportunity to liberate himself: After a quarrel with some of the men in the group while passing through Texas, he escaped to Mexico, where slavery was illegal.

If Green had made it to California, he would have encountered other enslaved people working in the gold mines and on ranches in the Sonoma Valley—as well 300,000 migrants of all nationalities who had arrived to this region by 1860. The slave population included not just African Americans, but Native Americans as well. In fact, Native American slavery was legalized in California in 1850 with the state legislature’s passage of the Act for the Government and Protection of Indians. Through this legislation, Native Americans had to provide documentation of employment or they would be arrested for vagrancy and sold to the highest bidder.

While the traditional history of the American frontier has long been one of white settlers in conflict with indigenous people, recent scholarship has rewritten that narrative, revealing it to be a far more complex place. Settling new territory required hard labor, and even as the Abolitionist movement grew back East, economic incentives on the frontier outweighed moral imperatives.

Daina Ramey Berry is the Michael Douglas Dean of Humanities and Fine Arts at the University of California, Santa Barbara. She is a scholar of the enslaved and the award-winning author/editor of books on slavery including The Price for Their Pound of Flesh, the Value of the Enslaved, from Womb to Grave, in the Building of a Nation. Follow her on twitter @DainaRameyBerry.

Nakia D. Parker is an assistant professor of history at the Michigan State University. Her research is on the history of gender, slavery and migration in the Choctaw and Chickasaw Nations.