Despite the horrors of slavery, it was no easy decision to flee. Escaping often involved leaving behind family and heading into the complete unknown, where harsh weather and lack of food might await.

Then there was the constant threat of capture. So-called slave catchers and their dogs roamed both sides of the Mason-Dixon line, nabbing runaways—and sometimes free Black people like Solomon Northup—and transporting them back to the plantation, where they would be whipped, beaten, branded or killed.

Yet those willing to brave the risks did have one main ally: the Underground Railroad, a vast, loosely organized network of constantly-changing routes that guided Black people to freedom.

All told, in the decades preceding the Civil War, up to 100,000 Black people escaped slavery. Some went to Mexico or Spanish-controlled Florida or hid out in the wilderness. Most, though, traveled to the Northern free states or Canada.

1: Getting Help

Harriet Tubman, circa 1860s. Library of Congress

No matter how courageous or clever, few enslaved people threw off their shackles without at least some outside help. Assistance could be as slight as clandestine tips, passed by word of mouth, on how to get away and who to trust. The luckiest, however, followed so-called “conductors,” such as Harriet Tubman, who, after escaping slavery in 1849, devoted herself fully to the Underground Railroad.

In about 13 trips back to the Eastern Shore of Maryland, where she had been brutally mistreated as an enslaved child, Tubman rescued some 70 people, mostly family and friends. Like her fellow conductors, Tubman cultivated a network of collaborators, including so-called “stationmasters,” who stashed her charges in barns and other safe houses along the way.

Tubman knew the Maryland landscape inside and out, generally following the North Star or rivers that snaked north. She knew which authorities were susceptible to bribes. And she knew how to communicate—and gather intelligence—without being caught.

She would, for example, sing certain songs, or mimic an owl, to signify when it was time to escape or when it was too dangerous to come out of hiding. She also mailed coded letters and sent along messengers.

2: Timing

Over the years, Tubman developed certain extra strategies for keeping her pursuers at arm’s length. For one, she usually operated in winter, when longer nights allowed her to cover more ground. She also preferred leaving on Saturday, knowing that no notices about runaways would appear in the newspaper until Monday (since there was no paper on Sunday.)

Tubman carried a pistol, both for protection and to intimidate those in her care who considered turning back. In addition, she brought drugs with her, using them when a baby’s cries threatened to give away her group’s position. “I never ran my train off the track,” Tubman would later state, “and I never lost a passenger.”

12 Gallery 12 Images

3: Disguises and Hiding

To return again and again to Maryland, Tubman often relied on disguises, dressing as a man, an elderly woman, or a middle-class free black depending on the situation. Her fellow conductors made similar use of costumes. They might, for example, enter a plantation posing as a slave in order to round up a group of escapees.

Conductors also needed disguises, or at least nicer clothes, for the charges in their care: They couldn’t very well flee in tattered slave rags without attracting unwanted attention.

Some sartorial efforts bordered on genius. In Georgia, a light-skinned enslaved woman posed as an injured white gentleman, with bandages on her face and her right arm in a sling, while her darker-skinned husband pretended to be under her possession. Traveling openly by train and boat, they survived several close calls and ultimately made it to the North.

Frederick Douglass likewise escaped slavery hiding in plain sight. Boarding a train dressed as a sailor, he flashed a sailor’s protection pass, borrowed from an accomplice, to fool the conductor. “Had the conductor looked closely at the paper,” Douglass would later write, “he could not have failed to discover that it called for a very different looking person from myself.”

By contrast, other runaways took extreme measures to conceal themselves. Desperate to avoid her master’s unwanted sexual advances, one enslaved woman hid for seven years in an attic crawlspace. Another lodged himself inside a wooden crate and shipped himself from Richmond, Virginia, to abolitionists in Philadelphia.

4: Codes, Secret Pathways

Harriet Tubman, far left, with family and neighbors at her home in Auburn, NY, circa 1887. MPI/Getty Images

The Underground Railroad scarcely existed in the Deep South, from which very few slaves escaped. Though pro-slavery sentiment wasn’t quite as strong in the Border States, those who abetted enslaved people there nonetheless faced the constant threat of being ratted out by their neighbors and punished by the authorities.

They therefore took great pains to keep their operations secret, which they did, in part, by communicating in code. A stationmaster, for example, might receive a letter referring to incoming fugitives as “bundles of wood” or a “parcel.” The words “French leave” indicated a sudden departure, whereas “patter roller” entailed a slave hunter.

On occasion, runaways might use a secret chamber or secret pathway, which would come to epitomize the Underground Railroad in the popular imagination.

5: Buying Freedom

For much of its length, though, the Underground Railroad operated openly and brazenly, despite the passage of the 1850 Fugitive Slave Act, which mandated harsh punishments for those found to have aided runaways. Some stationmasters claimed to have hosted thousands of fugitive slaves and very much publicized their actions.

A former enslaved man-turned-stationmaster in Syracuse, New York, even referred to himself in writing as the city’s “keeper of the Underground Railroad depot.”

Meanwhile, so-called “stockholders” raised money for the Underground Railroad, funding anti-slavery societies that provided ex-slaves with food, clothing, money, lodging and job-placement services.

At times, abolitionists would simply buy an enslaved person's freedom, as they did with Sojourner Truth. They also used the courts, suing, for example, to secure the release of Truth’s five-year-old son. Additionally, they fought to change public opinion, financing speeches by Truth and myriad other ex-slaves to bring the atrocities of bondage to light.

6. Fighting

When all else failed, Underground Railroad participants would occasionally form large groups to forcibly liberate fugitive enslaved people from captivity and intimidate slave catchers into returning home empty-handed. Perhaps not surprisingly, John Brown was among those who favored brute force.

Prior to his failed revolt in Harpers Ferry, Brown led a group of armed abolitionists into Missouri, where they rescued 11 enslaved people and killed an enslaver. Hotly pursued by pro-slavery forces, Brown then took the fugitives on a 1,500-mile journey through several states, finally depositing them safely in Canada.