What old maps say about environmental racism

Maps drawn by the US government in the 1930s made racial segregation an official promise of public policy. Those maps, and the policies they underpinned, paved the way for today’s segregated cities – and ongoing environmental degradation for Black Americans.

Illustration by  Lucas Peverill

Illustration by Lucas Peverill

While in a used bookstore in 2005, John Huggins stumbled across a sketch of lines and dots in reddish ink. Printed on the back of a 1952 fundraising flyer for the Travis County Tuberculosis Association, the red dots depicted cases of the disease – and deaths from it – in and around Austin, Texas.

Due to privacy concerns, epidemiological maps today don’t show health data as individual points. “It’s something that you just don’t find anywhere anymore,” says Huggins, a research geographer at the US Department of Housing and Urban Development – not speaking in his official role or representing the official positions of the agency. Cases of tuberculosis clustered in the southeast corner of Austin, an area home to many of the city’s Black and Latinx residents.

The sketch from the bookstore reminded Huggins of a more official map. In 1934, the US federal government drew a map dividing Austin into neighbourhoods, each rated according to the perceived risk of giving out home loans to its residents. Supposedly risky areas were colour-coded red, or “redlined” – often because the residents were Black.

Huggins had a hunch that the two maps would line up, so he created digital versions of each and superimposed them. Sure enough, the densest dot clusters were within redlined areas. Huggins couldn’t be certain of a causal relationship, but it made sense: many scholars have argued that the federal government and the private sector used mortgage maps like this to decide which neighborhoods would receive investment for home construction and repair. Huggins tracked down data from the 1950 census and found that the areas that suffered most from tuberculosis also had the highest number of homes without running water, a risk factor for tuberculosis.

Maps, often seen as neutral depictions of the world as it is, are anything but. Maps must be made, and mapmakers face choice after choice in how, exactly, to represent space. In so doing, they have the power to influence how others see the world, and thus how they act in it.

Austin was not alone with its redlining maps. Largely in the late 1930s, the government created such maps for 239 cities, and for decades afterward, these maps and the ideas they embodied shaped the actions of realtors, bankers, and federal housing officials. The maps were one of the tools used to build American segregation, and their shadow stretches into a range of realms today, including – as Huggins’ tuberculosis study perhaps suggests – the environment.

“Segregation is actually a social-ecological, systematic thing,” says Morgan Grove, a research forester with the US Forest Service. “It includes water quality, infant mortality, tuberculosis, urban heat island, canopy cover, and other things that we think of as ecological or environmental.”

Redlining maps like the one in Austin were drawn up by the Home Owners’ Loan Corporation (HOLC), a short-lived New Deal agency that refinanced mortgages during the Great Depression. Their neighbourhood ratings – from A (best) to D (hazardous), with the latter coloured red – helped to decide which homeowners would get help and which would be left out. HOLC officials based the ratings on housing quality, price range, and factors such as environmental conditions. In assigning a D grade to a neighborhood in East St. Louis, Illinois, for instance, one HOLC evaluator noted “smoke from nearby industrial plants.” The Oak Cliff neighborhood in Houston, Texas received a hazardous rating in part due to the presence of a fertiliser factory. The evaluation for one all-Black D neighbourhood in Durham, North Carolina mentioned a trash dump.

The HOLC’s mapmakers, who were white, often assigned C or D ratings to neighbourhoods inhabited by Black residents, regardless of other factors. Their map descriptions employed eerie language to do this, noting “infiltration of subversive racial elements” or simply “infiltration of Negroes.” The HOLC stopped issuing loans in 1936, but the agency’s maps, and the racial logic they endorsed, lived on in later agencies like the Federal Housing Administration.

Grove explains that the maps became part of the process for discriminating between neighbourhoods for investment. In the wake of World War II, the Federal Housing Administration subsidised a massive expansion of US home ownership, but funds were targeted largely toward white people in non-redlined areas. That pattern of resource investment can sometimes still be seen today. For example, Grove has shown that redlined areas in Baltimore, Maryland tend to have sparser tree canopy cover, a difference in the urban landscape that parallels low scores on the maps made for the city in 1937.

The HOLC’s maps are also reflected elsewhere in the environment. Between 1946 and 1965, the Hillside neighbourhood of Indianapolis, Indiana was home to a smelting facility that stored lead slag in open-air piles. Some of that lead persisted in the ground for years. Researchers have linked lead exposure to health and social impacts including anaemia, hypertension, kidney disease, behavioural disorders, and even crime. In the early 2000s, local health officials took blood samples from residents of Hillside and nearby areas. The children they sampled had more lead in their blood than kids in other parts of the city – with blood lead levels two to four times higher than average.

The Home Owners’ Loan Corporation area description for the part of Indianapolis that today includes the Hillside neighborhood.   Mapping Inequality  (CC BY-SA 4.0)

The Home Owners’ Loan Corporation area description for the part of Indianapolis that today includes the Hillside neighborhood. Mapping Inequality (CC BY-SA 4.0)

Decades earlier, federal mapmakers had deemed the area that now includes Hillside “hazardous” and coloured it red. Their report listed what they called the zone’s detrimental influences: “Older type houses. RR tracks and factories. Part of section occupied by lower type negroes.” The description pinned the Black population of the area at 60%. During the 1950s and 60s, when the lead facility operated, many white residents began to leave Hillside for the new suburbs. Today, the neighbourhood is over 90% Black.

“The money never comes to us,” Hillside Neighborhood Association President Anna Carter told The Indianapolis Star in 2015. “They keep going around us. They keep going past us and leaving us here. That just cannot continue to happen.”

In 2017, the Environmental Protection Agency announced that it had finally finished removing lead-contaminated soil from hundreds of properties in the neighbourhood.

The long environmental legacy of redlining shows that maps are more than just ink or pixels. “Mapmaking is power,” says Kishi Animashaun Ducre, the director of the Center for Social Justice and Civil Liberties at Riverside City College. When analysing these visual representations of space, she says, people should ask critical questions: Who made the map? And why?

Maps, she notes, typically show a physical environment, but they rarely show the people that live in it.

Ducre recounts a story from her days as an activist working with grassroots organisers in northern Louisiana to oppose a uranium enrichment facility. A multinational conglomerate had proposed building the plant in a small, majority-Black town, and released a map of the road they hoped to build to the facility. The proposed road cut through two Black communities that had existed in the area since the end of slavery, but the map didn’t include the boundaries or names of either neighbourhood.

Huggins’ tuberculosis map, in contrast, showed people – their illnesses and deaths, anyway. The HOLC mortgage map he compared it to was one backed by the power of the federal government.

Where researchers lack consensus, however, is on exactly how that power influenced mortgage lending practices. “We can’t say … ‘This particular map caused the neighborhood not to get the home loans or grants they needed to improve their homes,’” says Ducre. “But we know that these things are happening in concert with one another.” Some scholars have argued that the influence of the HOLC maps has been overstated because their circulation was relatively limited. David Freund, a historian at the University of Maryland, College Park, isn’t convinced that the maps were in limited circulation. “But even if they were,” he says, “what’s most important is that these maps codify something, a set of shared beliefs and assumptions that permeated the real estate industry and [Federal Housing Administration] officials. This was how they practiced, regardless.”

Indeed, the power of mapping hints at its broad significance in housing policy. These HOLC maps, with their pretense of objectivity, emerged shortly after real estate became a profession complete with its own specialised knowledge. “This is very much a moment in the efforts of the real estate and development industries to establish themselves as professionals,” says Freund . “A lot of different industries were really focused on making themselves appear scientific, including the social sciences, the real estate industry.”

People have a certain respect for maps. As Manuel Aalbers, a geographer at the University of Leuven, says: “A map is often believed to be objective, neutral, scientific.” They are often seen as authoritative representations of reality rather than visual arguments that can be challenged and rejected.

Despite their ostensible neutrality, mapmakers are in fact motivated by their own interests, whether those interests take the form of deliberate racism or unconscious bias. It’s a point Aalbers stresses: “they are always representative of the interests behind the people,” he says.

In the case of HOLC maps, those interests were often white interests. And those white interests manifest even in today’s environment. Take Oakland, California. Large swaths of West Oakland were redlined, or given the next-lowest grade, including every part of the city inhabited by more than a few Black people. Only neighbourhoods with negligible Black populations, or no Black residents at all, received higher ratings. One such neighbourhood about a mile north of Lake Merritt – a body of water that splashed into recent headlines when a local white woman called police on a Black family barbecuing near the shoreline – was classified as “still desirable,” for instance, but had just “one wealthy family” of African Americans.

The HOLC residential security map for Oakland, California.   Mapping Inequality  (CC BY-SA 4.0)

The HOLC residential security map for Oakland, California. Mapping Inequality (CC BY-SA 4.0)


Those who could afford to leave the redlined areas of West Oakland were mostly white, and until the 1960s the local government actively pushed low-income people and people of colour to settle in the area, especially near shipping ports. This left a legacy of environmental racism in the form of air pollution. A 2016 study demonstrated that, compared to other parts of the city, West Oakland suffers from more nitrogen dioxide and particulate matter, common pollutants spewed from the trucks and boats that frequent the city’s ports. Not surprisingly, then, the study found a correlation between the percentage of Black residents and the concentration of nitrogen dioxide in the air in Oakland. Research has linked this kind of pollution to health effects including asthma. Nationwide, Black Americans have higher asthma rates than white Americans, a disparity that has grown since the 1990s – and in 2014, they were nearly three times more likely to die from causes related to asthma.

The relationship between Oakland’s HOLC maps and its environmental injustice will likely change, since the city is quickly gentrifying. The study notes an influx of whites into historically Black parts of the city, and as Black residents are priced out, those areas are also seeing a more rapid reduction in air pollution than the areas to which displaced Black residents are moving.

It underscores the point that these are not always hard and fast relationships. “We can’t just use a map to stand in place of understanding,” Grove says. He emphasises the need, when looking at environmental justice, to understand both pattern and process. The old HOLC maps are a pattern: a pattern influenced by the racist designs of the mapmakers. But those maps did not determine one set course for redlined neighbourhoods.

Grove points to another finding from his environmental justice research: In Baltimore, predominantly Black neighborhoods are more likely to have parks within walking distance. In the context of scholarship on environmental racism, that might seem surprising. But even this result emerged from racism-laden processes. In the initial era of HOLC maps, Black people were segregated in areas with less access to parks. What changed was the racial composition of the city. It was only after many white residents of Baltimore left for the suburbs that Black people were able to disperse into other parts of the city and thus gain more access to parks.

Research linking HOLC maps and environmental racism consists of a few geographically scattered studies, such as those of Baltimore and Oakland. Historians first connected HOLC maps to segregation in the 1980s, around the same time that academics began researching environmental racism. But even though these fields have grown in parallel, relatively few researchers have looked at their intersection.

“If you want to understand the ecology of cities, you have to actually account for segregation,” says Grove. One part of that, given the power of cartography, will be delving further into the environmental ramifications of these maps.

Edited by Nathan Mifsud and Diana Crow