There is a disparity across racial groups in incarceration rates in the United States today. But this is not a recent phenomenon: a recently published sociological study argues this dates back to the late 1800s.

Since 1970, the percentage of Americans in prison has skyrocketed; the incarceration rate is especially pronounced among blacks. Though it’s often assumed that the racial disparity came along with the surge in incarceration, a recent study by a sociologist at Harvard suggests that the disparity originated earlier, with the emigration of blacks from the South. Not only was the racial disparity in incarceration higher in the North to begin with, but it rose sharply in the North after 1880, even while dropping sharply in the South after 1900. What exacerbated the racial disparity in the North was the fact that blacks were competing with lower-class immigrants from Europe, many of whom—particularly the Irish—had come to dominate law enforcement and were looking for any excuse to arrest blacks. In a sense, the Irish—who, ironically, had gotten a reputation as troublemakers when they first immigrated—traded places with blacks. “As the incarceration rate of Irish immigrants and their children in Great Migration states declined from 245 to 158 people per 100,000 between 1880 and 1950, the nonwhite incarceration rate leapt from 203 to 594.”

Muller, C., “Northward Migration and the Rise of Racial Disparity in American Incarceration, 1880–1950,” American Journal of Sociology (September 2012).

This is more evidence that the North has had a long history of issues over race after the Civil War. The typical narrative often doesn’t allow for this; the story often goes that the South was the racist and discriminatory part of the country and the Jim Crow laws prove this. But the North may not have been much better. In addition to these differences in incarceration rates, there is evidence of:

1. Increasing levels of residential segregation between whites and blacks emerging in many Northern cities in the early 1900s. As the Great Migration picked up, blacks were pushed to live in black areas, not in white neighborhoods. For example, the thousands upon thousands of blacks who entered the city were forced into the Black Belt. See the book American Apartheid, among other research.

2. Many smaller Northern communities had “sundown laws” that did not allow blacks to stay in the community after dark. While blacks had unprecedented residential mobility in the two decades after the Civil War, these new sundown rules pushed blacks back into major cities. See the book Sundown Towns.