Slave Fugitive: Eliza Harris of Uncle Tom's Cabin

Yes, there was a real Eliza.  The story in "Uncle Tom's Cabin" written by Harriet Beecher Stowe is based on that of a slave woman, mother of a two-year-old child.  She learned that her slave owner was going to sell some of his slaves, including her baby.  Fortunately she lived close to the Ohio River, the line between slave and free states.
She took her baby in her arms and walked all night.  Some winters the river would freeze, and she hoped this would be one of them.  However when she arrived at the river early in the morning she discovered that it was only partially frozen.  There were ice chunks floating in the river.  Crossing on the ice would be impossible.
She knocked on the door of a home near the river, and was invited in.  She thought her baby may freeze to death if she stayed outside.  She hoped to recruit herself and try to get across the river the next day. 
However, her pursuers did not give her the opportunity.  As the approached the property where she was staying, she fled to the river.  She jumped onto the closest ice flow, using it like an iceberg.  SHe had to carefully pick her way from ice chunk to ice chunk.  Often they would sink after she had been on them a time.  A couple times she had to throw her baby to the next ice, and then jump as far as she could into the water, and climb onto the next ice flow.  Her pursuers thought for sure she would drown.  However, she made it across.  She sought refuge and was quickly taken to the home of John Rankin, a local minister and prominent member of the Under-ground Railroad in Ripley, Ohio.  From there she was sent to the home of Levi and Katie Coffin, referred to as the presidents of the UGRR.  This was in Indiana.
Eliza and her baby headed north, protected and transported by the UGRR.  Likely she traveled by wagon with a false bottom.  The story of her daring escape was published in the Harriet Beecher Stow novel in 1851.