Starting in the 1930s, a federal agency known as the Home Owners’ Loan Corporation (HOLC) sent dozens of surveyors to neighborhoods across the country. Often relying on the knowledge of local realtors, banks, and city agencies, the surveyors tallied up statistics about race, ethnicity, mortgage rates, and housing conditions. From these notes, the HOLC stamped thousands of neighborhoods with rankings on a graded scale, from A to D, with D-grade neighborhoods marked on maps in red.

It was this cartographic color palette that gave rise to the term “redlining.” In recent years, these maps and the broader phenomenon of redlining have become some of the most widely used and shocking demonstrations of institutional racism in American life. The maps seem to tell a straightforward story: the federal government engineered racial segregation by specifically identifying Black neighborhoods and eliminating them from federal housing programs, setting these neighborhoods up for permanent disinvestment and marginalization.

Redlining, however, wasn’t only about race. In fact, in many American cities, the majority of redlined neighborhoods didn’t have any Black residents living in them at all. If redlining maps were not just maps of race, then what were they maps of? They were maps that cataloged and reproduced the spatial order of a much broader system of inequality and injustice, one in which race mingled with other markers of social disinvestment. Redlining maps endorsed ideas about risk and value that suited the needs of private finance, laundering all sorts of coded ideas about social order behind the neutral geographic assessment of good and bad neighborhoods. Getting the history of these infamous maps right is crucial if we want to understand how patterns of urban inequality continue to undermine social integration and economic justice in the present day.

In the Hough’s Neck and Germantown neighborhoods of Quincy, Massachusetts, jutting out into the Atlantic Ocean with impressive seaside views, HOLC surveyors found no foreign-born families and no Black residents. Sixty percent of homes here were owner-occupied. The surveyors graded the area D on their description card, and on the map, they inked it red. They made a similar conclusion at Winthrop Beach, north of Boston, where they observed a “resort location” and a “good beach” but nonetheless assigned the area a D.

In one tract of the Nonantum section of the Boston suburb of Newton, the surveyors found 60 percent Italian families and 0 percent Black; they noted “good schools, churches, etc.” This neighborhood, too, got a D rating and a splash of red. In Boston’s Charlestown district, where the surveyors found 40 percent Canadian families and 0 percent Black families, as well as a neighborhood that boasted “proximity to Boston commercial area,” the HOLC made the same conclusion: D grade, red map.

To understand why neighborhoods like Hough’s Neck, Winthrop Beach, Nonantum, and Charlestown were redlined, even though they had no Black residents at all, it’s important to realize that the raison d’être of the HOLC programs wasn’t enforcing racial apartheid. It was managing financial stability and risk. The HOLC didn’t refer to its documents as “redlining” maps, but rather as “security” maps. And its evaluations of financial risk and security rested heavily on stereotypes about what kinds of people and places were risky or secure—stereotypes that continued to shape cities long after the HOLC was disbanded in 1954.