Reading the 1938 HOLC Residential Security Maps

Between 1935 and 1940 the federal Home Owners' Loan Corporation produced 'residential security maps' for over 200 American cities. Neighborhoods were graded A (green, 'best') through D (red, 'hazardous'). Black neighborhoods, mixed-race neighborhoods, and neighborhoods near Black ones were systematically graded D — the practice the maps gave its name: redlining.

The grades fed directly into Federal Housing Administration underwriting standards. For three decades, mortgage credit was withheld or made costlier in red-lined neighborhoods. The maps were not made public during their operational use; their historical existence was confirmed and publicly documented after civil-rights-era investigations.

The University of Richmond's Digital Scholarship Lab now hosts the digitized maps and the accompanying area-description sheets in a project called Mapping Inequality. The sheets quote the appraisers in their own words — explicit references to 'infiltration' by Black residents lowering grade scores appear on almost every D-graded sheet.

Reading the maps and sheets directly is one of the most efficient ways to understand how mid-century federal policy encoded racial segregation into the American housing finance system.

The practical mechanics of reading the HOLC maps and area description files are worth describing because the documents yield more on close reading than their summary characterizations tend to suggest. The maps themselves are color-coded city plats with neighborhoods outlined and labeled by HOLC's grading system. The area description files are the accompanying documentary apparatus: a multi-page form for each graded neighborhood containing demographic data, housing-stock data, physical-condition assessment, mortgage-availability assessment, and an open-ended narrative section on 'clarifying remarks.' The narrative sections are where the explicit racial reasoning appears.

The standard Federal Reserve Bank of Chicago methodology for linking 1930s grades to present-day outcomes uses the Mapping Inequality project's geocoded shapefiles to attach HOLC grades to modern census tracts. The resulting dataset allows direct statistical comparison of tracts that were graded D in the 1930s against tracts that were graded A in the same city, controlling for present-day housing-stock characteristics, median household income, demographic composition, and other potentially confounding variables. The principal finding across this literature is that 1930s grades retain substantial predictive power for present-day mortgage-rejection rates, median home values, and credit-score distributions even after controlling for the modern variables. The neighborhood-level structural effects of the 1930s regime are still detectable in the 2020s data.

Reading specific area description files is the most direct way to understand what 'redlining' actually meant in operational practice. The Philadelphia area description files, for example, include narrative sections describing specific neighborhoods as 'rapidly being infiltrated by a low grade Italian population' or as 'a colored district.' The Detroit files describe specific neighborhoods as containing 'a number of Jewish families' as a downward-grading factor. The Brooklyn files describe specific blocks as 'subversive racial elements.' The language is candid; the appraisers were not trying to hide what they were doing. The grades were a technical instrument of federal housing-finance policy, and the technical instrument was openly racial.

The complementarity between the HOLC maps and the Federal Housing Administration's underwriting standards is the part of the picture that is most consequential for understanding the scale of the federal role. The HOLC maps were produced for internal HOLC use and were not formally shared with the FHA. The FHA, however, was developing its own neighborhood-risk classification system during the same period and drew on the same appraisal framework. The FHA Underwriting Manual's 1938 edition explicitly recommended restrictive racial covenants as a desirable feature of insurable subdivisions. The FHA's operational practice during the 1940s and 1950s redlined neighborhoods on substantially the same pattern as the HOLC maps documented. The combined effect was that federally insured mortgage capital, the principal driver of the postwar suburban expansion, flowed almost exclusively to white-occupied neighborhoods and almost not at all to neighborhoods with substantial Black, Latino, or recent-immigrant populations.

The mechanism by which the federal redlining regime produced the modern racial wealth gap is direct. Home equity is the principal source of intergenerational wealth transfer for middle-class American families. The FHA-insured suburban single-family home, purchased in the 1940s or 1950s with a long-amortization low-down-payment federally insured mortgage, produced equity gains over the subsequent decades that the purchasing families' children and grandchildren inherited. Black families who were excluded from FHA insurance, who instead rented or purchased homes through the predatory contract-buying schemes Beryl Satter documents in 'Family Properties,' did not accumulate the same equity. The Brookings Institution's 2020 analysis of the federal-housing-policy origins of the modern racial wealth gap attributes a substantial share of the current wealth differential to the operational consequences of the 1934-1968 federal redlining regime.

The Mapping Inequality project's digitization of the maps and area description files has produced a public-facing documentary infrastructure that did not exist before 2016. The project's online interface allows readers to view the colored maps, search the area descriptions, and overlay the historical grades on modern street maps for any of the more than 200 cities covered. Readers in those cities can locate their own neighborhoods in the 1930s grading and read the contemporaneous appraiser's narrative on the neighborhood. The pedagogical effect of the immediate-visual-recognition experience — of seeing one's own neighborhood color-coded under a 1937 appraisal — has been one of the principal contributions of the digitization project to public understanding of mid-century housing policy.

The Mapping Inequality project's online interface, hosted at dsl.richmond.edu/panorama/redlining/, provides the principal modern access point for the HOLC area description files and the digitized maps. The interface allows readers to search the area descriptions by city, by neighborhood, by grade, and by specific demographic or physical-condition characteristics. The historical maps can be overlaid on modern street maps to allow readers to locate their own neighborhoods in the 1930s grading framework. The interface supports the broader public-engagement infrastructure that the project has produced across its post-2016 operational period.

The cumulative subsequent scholarship on the documentary implications of the HOLC framework has been substantial. The Federal Reserve Bank of Chicago's 2018 study 'The Effects of the 1930s HOLC Redlining Maps,' the National Bureau of Economic Research's parallel subsequent working-paper series, and the broader academic engagement with the documentary record have produced substantial documentation of the long-term effects of the 1930s federal-housing-policy regime on contemporary residential outcomes. The platform's pathways pages cover the principal Community Reinvestment Act enforcement and fair-lending complaint intake routes.