The
Underground Railroad was a network of secret routes and
safe houses used by 19th-century
enslaved people of
African descent in the United States in efforts to escape to
free states and
Canada with the aid of
abolitionists and allies who were sympathetic to their cause. The term is also applied to the abolitionists, both black and white, free and enslaved, who aided the fugitives. Various other routes led to
Mexico or overseas. An "Underground Railroad" running south toward
Florida, then a
Spanish possession, existed from the late 17th century until shortly after the
American Revolution. However, the network now generally known as the Underground Railroad was formed in the early 19th century, and reached its height between 1850 and 1860. One estimate suggests that by 1850, 100,000 slaves had escaped via the "Railroad".