The use of racially discriminatory housing maps in the 1930s, a practice known as “redlining,” perpetuated multi-generational cycles of poverty and segregation that continue today. While redlining shaped cities, its legacy does not fully explain current urban patterns of privilege and disadvantage, finds a new study.
The Proceedings of the National Academy of Sciences (PNAS) published the research, based on the metropolitan area of Portland, Oregon.
“Our research shows that simply mapping redlined neighborhoods does not capture the complex, evolving picture of inequality in cities,” says Jola Ajibade, co-lead author of the study and associate professor of environmental sciences at Emory University. “When we keep focusing on redlining we miss the fact that most cities in the United States have grown far beyond their original city centers. At the same time, gentrification and displacement create new and uneven landscapes of risk and opportunity.”
Kevan B. Moffett, associate professor of environmental hydrology at Washington State University, Vancouver, is co-lead author of the PNAS paper.
In 1935, the Federal Home Loan Bank Board tasked the Home Owners’ Loan Corporation, or HOLC, to create “residential security maps” for real-estate investments in cities throughout the country. These areas were ranked and color-coded. Neighborhoods were outlined in green to indicate those most desirable for investment, blue to indicate some desirability, yellow to indicate they were on the decline and red to indicate they were at the highest risk for mortgage support.
The areas mapped at highest-risk, or redlined neighborhoods, included most of the African-American and other racial minority urban households and tended to be in the older areas of city centers. The discriminatory practice of basing mortgage eligibility on these maps, known as redlining, limited opportunities for home ownership and wealth creation among minority populations.
To explore current disparities in Portland, the researchers analyzed publicly available socio-economic data along with more than 100 environmental and health indicators. The analyses considered a modern-day map of the city, while also factoring in the former borders of HOLC “residential security maps.”
Highlights of their findings include:
“Our findings add complexity, but a better understanding, of how many different socio-economic and environmental factors shape people’s health and quality of life,” Ajibade says. “To build healthier, more equitable cities, policymakers and planners must look beyond the narrow lens of redlining.”
While the study focused on Portland, the researchers hope their methods will be applied to other cities throughout the United States.
“This study offers a new, data-driven approach to identify where environmental and health inequities persist, where they are shifting, and how policies and investments in efforts such as tree planting, improving housing, health interventions and disaster-risk reduction can make the biggest difference,” Ajibade says.
The work was supported by the National Science Foundation (2010014).
Proceedings of the National Academy of Sciences
Data/statistical analysis
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Today’s urban inequality goes far beyond legacy of ‘redlining,’ study shows
14-Sep-2026