Slavery in the United States, by decade

Posted to Maps  |  Tags:  |  Nathan Yau

Mapping slavery from a historical perspective is a challenge, because many old maps and estimates are at the county level. Boundaries changed and counting methods changed, which provides for variation over time and geography. Cartographer Bill Rankin tries to find balance between accuracy and readability in a set of maps that show slavery in a grid layout from 1790 to 1870.

Rankin made a map for each decade, but the most interesting one that shows all the data at once. Size of each circle represents the peak number of slaves per 250 square miles. Color represents the year this peak occurred.

[This] map shows the peak number of slaves in each area, along with the year when slavery peaked. Except in Delaware, Maryland, and eastern Virginia, slavery in the south was only headed in one direction: up. Cartographically, this map offers a temporal analysis without relying on a series of snapshots (either a slideshow or an animation), and it makes it clear that a static map is perfectly capable of representing a dynamic historical process.

See the complete set.

Favorites

Jobs Charted by State and Salary

Jobs and pay can vary a lot depending on where you live, based on 2013 data from the Bureau of Labor Statistics. Here’s an interactive to look.

Watching the growth of Walmart – now with 100% more Sam’s Club

The ever so popular Walmart growth map gets an update, and yes, it still looks like a wildfire. Sam’s Club follows soon after, although not nearly as vigorously.

Pizza Place Geography

Most of the major pizza chains are within a 5-mile radius of where I live, so I have my pick, …

The Most Unisex Names in US History

Moving on from the most trendy names in US history, let’s look at the most unisex ones. Some names have …