A list of sites used for the Underground Railroad is available online from the National Parks Service. Its website provides a list of sites organized by state. It also includes photos and a history of the sites.
In addition to photos of the sites, the National Parks Service's website lists the addresses of the Underground Railroad sites used, allowing curious homeowners to confirm whether or not their homes were used for the Underground Railroad.
Not an actual railroad, the Underground Railroad was a pre-Civil War network that helped slaves escape from the South. Although the network contained some white Northern abolitionists, the racial makeup of the network was mainly black. In fact, the History Channel reports that the Northern free blacks usually had little or no help from the white abolitionists.
Nevertheless, once slaves had escaped from a plantation, they would move from safe house to safe house, often called "stations" or "depots," where they would rest, eat and wait for word that it was safe to make the journey to the next stop. This would continue until the slaves made their way to safety, first to the North and then to Canada. According to PBS, it is estimated that more than 100,000 slaves escaped between 1810 and 1850.