early to mid 19th century, slavery issue (jan 23, 1800 – may 16, 1850)
Underground Railrod was a name for the network of secret routes and safe houses for runaway slaves, who tried to escape from slave states to the North. It was the African American abolitionists who established hiding places ans so started the underground railroad.
Added to timeline:
Timeline: Causes of the American Civil war by Veera Rakkolainen