The New York Times have published an interactive map of slavery in the southern United States in 1860, based on the census taken in that year. It is fascinating to see where the densest areas of slavery (over 80% of the population in that area) were; Abraham Lincoln regularly referred to it regularly and the map can even be seen in a portrait of his cabinet in 1864, when he read the emancipation proclamation. The map forms part of a timeline project the paper will be doing, marking the 150th anniversary the war. Blog posts will be published regularly on the anniversary of particular events, using material from the papers archives and comments from historians. You can follow the timeline here.