Harriet Ross was born into slavery in 1819 or 1820, in Dorchester County, Maryland. She was named after her parents, both held in slavery. She was raised under the harsh conditions of slavery, at age five or six, she began to work as a house servant. Seven years later she was sent to work in the fields. 

When Harriet Ross was still in her early teens, she suffered a head injury that effected her for her whole life. Standing up for another slave, she blocked a doorway to protect another field hand from an angry overseer. She never fully recovered.

Around 1844 she married a free black named John Tubman and took his last name.

In 1849, in fear that she, along with the other slaves on the plantation, was to be sold, and taken away from their families, she decided to run away. She set out one night on foot. With some assistance from a white woman, Tubman was on her way. Making use of the network known as the Underground Railroad, Tubman traveled nearly 90 miles to Philadelphia. She crossed into the free state of Pennsylvania with a feeling of relief to be free. 

Rather than remaining in the safety of the North, Tubman made it her mission to rescue her family and others living in slavery using the Underground Railroad. The following year she returned to Maryland and escorted her sister and her sister's two children to freedom. She made the dangerous trip back to the South soon after to rescue her brother and two other men. On her third return, she went after her husband, only to find he had another wife. So, instead, she found other slaves seeking freedom and escorted them to the North.