The Underground Railroad was a network of clandestine routes and safe houses established in the United States during the early- to the mid-19th century. It was used by enslaved African Americans primarily to escape into free states and Canada. The network was assisted by abolitionists and others sympathetic to the cause of the escapees. The enslaved persons who risked escape and those who aided them are also collectively referred to as the "Underground Railroad". Various other routes led to Mexico, where slavery had been abolished, and to islands in the Caribbean that were not part of the slave trade. An earlier escape route running south toward Florida, then a Spanish possession (except 1763–1783), existed from the late 17th century until approximately 1790. However, the network now generally known as the Underground Railroad began in the late 18th century. It ran north and grew steadily until the Emancipation Proclamation was signed by President Abraham Lincoln. One estimate suggests that by 1850, approximately 100,000 enslaved people had escaped to freedom via the network. Origin of the name Eric Foner writes that the first usage may have been a Washington newspaper in 1839, which stated that the railroad "went underground all the way to Boston." Political background For the enslaved people who "rode" the Underground Railroad, many of them considered Canada their final destination. An estimated 30,000 to 40,000 freedom seekers settled in Canada, half of whom came between 1850 and 1860. Others settled in free states in the north. Thousands of court cases for escaped enslaved were recorded between the Revolutionary War and the Civil War. Under the original Fugitive Slave Act of 1793, officials from free states were required to assist slaveholders or their agents who recaptured fugitives, but some state legislatures prohibited this. The law made it easier for slaveholders and slave catchers to capture African Americans and return them to slavery, and in some cases allowed them to enslave free blacks. It also created an eagerness among abolitionists to help enslaved people, resulting in the growth of anti-slavery societies and the Underground Railroad. With heavy lobbying by Southern politicians, the Compromise of 1850 was passed by Congress after the Mexican–American War. It stipulated a more stringent Fugitive Slave Law; ostensibly, the compromise addressed regional problems by compelling officials of free states to assist slave catchers, granting them immunity to operate in free states. Because the law required sparse documentation