A Visual History of the U.S. State Boundaries by Timeplots

This graphic is a visualization of the history of US state boundaries. It gives an overview of current and past state boundaries throughout the country's entire history, combining time and space in a sheet of paper.
Each key era in the formation of state boundaries history is indicated with a shade of blue on the graphic. With a centric U.S. map and a wide range of visual clues, the graphic shows not only the naturally formed boundaries such as waterways and terrains, but a story of how slavery influenced the formation of state boundaries, as well as stories of each individual state in the sidebars.