If slavery is not wrong, nothing is wrong.

-Abraham Lincoln

One-hundred-fifty-six years later, we’ve come to unilaterally praise Lincoln for his courageous leadership in the legal abolition of chattel slavery, accepting that his signature move was the product of whole-hearted morality and a clear-headed view of justice—not the result of a much more complicated story. In spite of Lincoln’s true motivations, however, there’s no denying that his actions forever changed the course of the United States, enabling millions of previously nominally-lesser, physically-equal human beings to seize their long-denied natural rights in the pursuit of a better life.

Abraham Lincoln, 16th President of the United States (1861-1865).

From an idealistic perspective, Lincoln’s 1863 Emancipation Proclamation uprooted 200+ years of injustice and utter brutality in a single document. From a realistic perspective, Lincoln’s proclamation merely marked the beginning of a task we’ve yet to finish—modern manifestations and not-so-subtle artifacts of slavery still persist to this day, evidence of our failure in carrying out Reconstruction.

How did we get there?

Pondering this question over the past week, I realized that I was, in fact, asking two questions: 1) how did we come to approve of the practice of chattel slavery within the 17th-, 18th- and 19th-century United States, and 2) how did we get to a point where chattel slavery was so widely practiced, to a point where the routine subjugation and dehumanization of innocent and equal individuals was downright common in the 19th-century United States? The first question, while no less important than the second, was too broad to effectively answer in a weeks’ time—perhaps even in a year’s, or several years’ time. On the other hand, the second question not only lent itself to more straightforward analysis, but to a more quantitative-focused, data-driven one: the perfect test subject for a digital approach to research.

George Washington, 1st President of the United States, depicted alongside bondspersons at Mount Vernon in an 1853 lithograph from The Granger Collection, NYC. Some of the bondspersons over whom Washington claimed ownership are likely included in the 1790 count of enslaved persons of Virginia in the visualizations below.

Having recently discussed the power of visualization in effective communication and the responsibilities that come with its employment, I dove into a trove of NHGIS census data from 1790-1850 seeking answers to my second question. How did the population of enslaved persons grow in these 60 years, and with what pattern? How did the proportion of enslaved persons within the United States change over time, both numerically and spatially? When did northern states begin to push for the abolition of slavery, and how did that affect the enslaved populations of southern states thereafter? What states exhibited steady free and enslaved population patterns, and which took more stochastic trajectories from decade to decade?

What might a comparative quantitative analysis of free and enslaved populations across the United States reveal about the spread of our “peculiar institution” over space and time? Ideally, the visualizations 1 2 3 4 below will spark and satiate your curiosity with respect to these questions as they have mine.

As one would reasonably expect, the primary trend in shifting slave populations revealed by each visualization is characteristic of the domestic slave trade’s impact on the Deep South: from 1820 to 1850, the enslaved populations of Alabama, Georgia, South Carolina, North Carolina, Mississippi and Louisiana skyrocket at rates of growth far outpacing those in Kentucky, Tennessee, Virginia, and Maryland. Whereas northern states gradually halted the practice of slavery over the early 19th century and the upper-southern states gradually grew its practice, the states of the far south and far west—the states where land was plentiful, cotton was king, and rebellious organization was rare—saw ballooning growth of the horrific practice.

While such observations aren’t necessarily surprising, I believe the above visualizations do more to effectively communicate how the United States arrived at its precarious perch in 1863 in comparison to a purely verbal explanation. Seeing is a wholly different means by which we absorb and process information as humans, and the sheer scale of our nation’s past sick practices are, in my mind, impossible to grasp without a latticework of different models representing that scale. Reading that the enslaved population of South Carolina grew from 107,094 humans in 1790 to 384,984 humans in 1850 delivers one form of shock; seeing it delivers another. Human nature dictates we’re bad at making sense of large numbers, but we owe it to those strong, courageous, persevering individuals who endured years upon years of criminal victimization to try.

Isaac Granger (1775-c.1850), an enslaved blacksmith at 3rd President of the United States Thomas Jefferson’s Monticello estate who was likely included in several of the counts of enslaved persons of Virginia in the visualizations above.

Because much of my week was spent collecting, cleaning, and processing NHGIS data to create the above visualizations, I’ll keep this week’s narration short, and leave you to ponder the other ways in which this expression of the spread of slavery changes your outlook on the subject. Before I end this, however, a disclaimer.

Recall that all models are wrong, including those above. There’s simply no way to project the infinite-dimensional space of the lives of 19th-century enslaved individuals onto a 2D computer screen without losing the vast majority of the story; therefore, it’s more important to consider what the visualizations don’t tell us about the lives of those represented than what they do. What hardships did each and every individual in the sum-total of the bars and boxes above endure? How did the day-to-day lives of bondspersons in Louisiana compare to those in Missisippi, and how did the lives of bondspersons in Georgia compare to those in Virginia?

To distill: what’s the history behind the data?

We work in the digital humanities, and while data is fascinating, it is dually a curse. It explains, clarifies, reveals. It abstracts, lies, and oversimplifies. It serves a narrow purpose, often leaving us with more questions than answers.

It’s our job to embrace those questions, to avoid hasty conclusions, and to ultimately seek the truth. While I hope the visualizations above may serve as a stepping stone in your journey towards such an end, I encourage you to seek the next stepping stone. By no means is this the final one.

  1. 1790-1850 US Enslaved Population, by state [Treemap]
  2. 1790-1850 US Total Population, by state [Treemap] 
  3. 1790-1850 US Enslaved Population, by state [Bar]
  4. 1790-1850 US Total Population, by state [Bar]