In the aftermath of the Great Depression, the U.S. government set out to evaluate the riskiness of mortgages — and left behind a stunning portrait of the racism and discrimination that has shaped American housing policy.
Now a new digital tool makes it easier than ever to see that history in high-resolution.
The project features the infamous redlining maps from the Home Owners' Loan Corporation. In the late 1930s, the HOLC "graded" neighborhoods into four categories, based in large part on their racial makeup. Neighborhoods with minority occupants were marked in red — hence "redlining — and considered high-risk for mortgage lenders.
Redlining was carried out in cities big and small, with the help of local realtors and appraisers. The maps and descriptions eventually made it into the National Archives.
A from "Mapping Inequality" takes scores of HOLC maps — previously accessible only in person at the Archives or in scanned images online — and embeds them on a single map of the USA. Selecting a city reveals the old map images; zooming in shows a color overlay over a modern map with street names and building outlines.

A team of scholars at four universities took seven months to build the project. More than 150 cities are included in the map, which was released last week to replace a version with fewer features. A key element of the new map is that many neighborhoods include the reasonthey were classified the way they were.
If you see that a neighborhood was redlined, ranked as "desirable" or fell somewhere in the middle, just click and you can find out why. "Infiltration of: Negroes" is a common fill-in-the-blank item explaining why a region was deemed hazardous.
"Respectable people but homes are too near negro area," reads a summary for a B-grade neighborhood in Richmond, Va.
"This is considered the most exclusive, or swank, section in Springfield," says the entry for one of the city's two A-classified neighborhoods. "The area is high restricted" — meaning it enforces strict rules barring non-white people from buying houses there.
, director of the Digital Scholarship Lab at the University of Richmond, co-designed the map. He says one entry in particular stands out for him as shocking: a spot in Camden, N.J., where a D-graded neighborhood abuts an A-grade, an unusual situation.
"It is 100% poor class Negroes practically all on relief," the "clarifying remarks" for the redlined neighborhood read. "A high wall, however, prevents their spread."
Another neighborhood in Camden, mostly occupied by Polish professionals, was graded "declining," one step above a redlined neighborhood. "Negro district on edge of section," the description reads, "but splendid cooperation of all residents in this section will always prevent spread."