Decades have passed since the end of the Jim Crow era in the United States. While segregation laws are no longer on the books, the legacy of the century-long period, which followed hundreds of years of institutional slavery, is evident across the country as wide socioeconomic gaps exist along racial lines.

Nationwide, the typical black household earns about $25,000 a year less than the typical white household. African-American workers are also more than twice as likely to be unemployed as white workers. Disparities such as these are not even across the country, however, and in some areas, socioeconomic gaps along racial lines are far greater.

Using data from the U.S. Census Bureau, 24/7 Wall St. created an index to measure socioeconomic disparities between black and white Americans by congressional districts to identify the worst congressional districts for black Americans. 

Several of the congressional districts on this list fall within some of the worst cities for black Americans. But unlike cities, towns, or counties, congressional districts are not managed by a central municipality. Because the typical congressional district represents about 700,000 people, districts vary in geographical size depending on population density and can span multiple cities or be encompassed within one city. No matter how large they are, the one thing residents of a given congressional district all share is the representative they send to Washington D.C. 

24/7 Wall St. discussed conditions within congressional districts with Andre Perry, a fellow in the Metropolitan Policy Program at the Brookings Institution. Perry explained that conditions within a given district are the product of a multitude of historical social and economic factors and therefore often reveal very little as to the efficacy of current political leadership. 

However, congressmen and congresswomen are elected to represent the best interests of their constituents at the national level by writing, amending, and voting on legislation that can benefit their district. As such, congressional representatives are in a unique position of power to address issues of social and economic inequality within their district. Civil rights and racial equality are central to the political platform of several representatives on this list. 

While congressional representatives do have unique political power to effect change, Perry explained that their tool box is also limited. “An individual congressperson can do a pet project here or there to bring relatively small amounts of capital to a district,” Perry said. For more comprehensive improvements in particular districts, however, broader congressional buy-in is necessary, he added.

Disparities in many of these areas are also a product of racial segregation. Perry explained that nationwide — even after controlling for variables like education, crime, and walkability — homes in black neighborhoods are priced 23% lower in white neighborhoods. And lower property values have far-reaching implications. “…Those revenues that are lost through devaluation are lost on education, infrastructure, quality policing, and all those things it supplies,” Perry said.

Perhaps not surprisingly, many of the congressional districts on this list fall partially or entirely within some of the most segregated cities in the country. These are the 25 most segregated cities in America.

Click here to see the worst congressional districts for black Americans

To determine the 30 worst congressional districts for black Americans, 24/7 Wall St. created an index consisting of six measures to assess race-based gaps in socioeconomic outcomes in each of the nation’s congressional districts. Creating the index in this way ensured that districts were ranked on the differences between black and white residents and not on absolute levels of socioeconomic development.

The seven measures — cost of living-adjusted median household income, poverty, adult high school and bachelor’s degree attainment, homeownership, and unemployment rates — are five-year estimates from the U.S. Census Bureau’s 2017 American Community Survey. To better represent the actual disparities in purchasing power in these districts, all income figures referenced are adjusted for cost of living according to the district’s state using regional price parities from the Bureau of Economic Analysis. 

For each measure, we constructed an index from the gaps between black and white Americans. The index was standardized using interdecile normalization so that outliers in the data would not skew results. We excluded districts where black residents comprised less than 10% of the population or where data limitations made comparisons between racial groups impossible.

With minor differences due to data availability, this methodology is also used to create the Worst Cities for Black Americans, and the Worst States for Black Americans. 24/7 Wall St. has published each of these stories within the last three years.