For over a century, historians have operated under the mistaken impression that exactly 618,222 men died during America’s Civil War. That number was always an estimate, with the Confederate casualties being based largely on meager data and some rather dubious extrapolation. So, what was the Civil War death toll?

Civil War Death Toll: How Many People Died during the Civil War?

New research conducted by demographic historian J. David Hacker has upended traditional Civil War death estimates. It turns out the death toll may have been higher…much higher. In fact, Hacker estimates the Civil War death toll at somewhere between 650,000 and 850,000, using the mid-point of 750,000 as his best guess.

In order to get that number, Hacker massaged various data sets, making numerous assumptions along the way. Breaking it down between Union and Confederacy proved impossible, due to uncertainty surrounding the loyalties of border state soldiers. Overall, this new estimate leaves much to be desired. The size of the confidence interval tells us that much. But unfortunately, it’s the best we’ve got…at least for now. Here’s more on new Civil War death toll estimates from The New York Times:

For 110 years, the numbers stood as gospel: 618,222 men died in the Civil War, 360,222 from the North and 258,000 from the South — by far the greatest toll of any war in American history. But new research shows that the numbers were far too low.

By combing through newly digitized census data from the 19th century, J. David Hacker, a demographic historian from Binghamton University in New York, has recalculated the death toll and increased it by more than 20 percent — to 750,000.

The new figure is already winning acceptance from scholars. Civil War History, the journal that published Dr. Hacker’s paper, called it “among the most consequential pieces ever to appear” in its pages. And a pre-eminent authority on the era, Eric Foner, a historian at Columbia University, said: “It even further elevates the significance of the Civil War and makes a dramatic statement about how the war is a central moment in American history. It helps you understand, particularly in the South with a much smaller population, what a devastating experience this was.”

(See The New York Times for more on the Civil War death toll)