EdBuild has released a report of what it calls the most segregated schools in the country.  The goal of the study was "[t]o explore how school district borders isolate the neediest students [by] conducted[ing] an analysis of each of these boundaries across the country."  It found that

A typical school district border in the United States separates a pair of districts whose student-age poverty rates differ by seven percentage points. The difference between the 50 most segregated neighbors ranges from 34 to 42 percentage points: an average that is more than five times the national mean. Among the 50 pairs, the wealthier school districts have a poverty rate of just 9 percent, while their neighbors average 46 percent— 400 percent higher. This means that wealthier peers enjoy a poverty rate that is less than half the national average; whereas their neighbors enroll over 150 percent more impoverished students than the average US district. The 50 higher-income areas are also far smaller enclaves of wealth– their schools serve 15,000 less students on average. Additionally, the average homes in the wealthier districts are worth $131,000 more than their neighbors’. Because local funds for education are tied to property wealth, high-poverty districts are not able to generate as many funds locally. In fact, even though several of the 50 high-poverty districts tax themselves at a higher rate than their neighbors, they generate $4,500 less per student from local taxes. The 50 most segregating borders are found in only 14 states. Ohio contains nine, more than any other state. Alabama has seven. New York and Pennsylvania each contain six. Twenty-nine borders, almost 60 percent of the top 50, are located in the Rust Belt region. States with countywide school districts, like those in the south and the west, are almost entirely absent from the list.

The five most-segregated were the following:

• Detroit Public Schools - Grosse Pointe Public School System: Difference in School-Age Poverty of 42.7 percentage points
• Birmingham City School District - Vestavia Hills City School District & Mountain Brook City School District Difference in School-Age Poverty of 42.3 & 42.0 percentage points
• Clairton City School District - West Jefferson Hills School District Difference in School-Age Poverty of 41.7 percentage points
• Dayton City School District - Beavercreek City School District & Oakwood City School District Difference in School-Age Poverty of 40.7 & 40.3 percentage points
• Balsz Elementary School District - Scottsdale Unified School District Difference in School-Age Poverty of 40.3 percentage points

The reports concludes that

When the Supreme Court established that desegregation orders could not be enforced across district boundaries, it significantly reduced the possibility of achieving meaningful integration. And because America relies so heavily on local property taxes to raise funds for education, the inability to cross district boundaries institutionalizes income segregation and contributes to vast funding disparities among public schools. In this report, we highlight the worst examples of socioeconomic segregation across school district borders as illustrations of a problem that can be seen all across the country. These divisions are harmful for all students, but especially for those who reside on the wrong side of these borders. There you will find 26 million children living within high-poverty school districts, effectively trapped by impermeable borders, while greater educational opportunities often are being enjoyed by their better-off peers right next door. The fact, too seldom acknowledged, is that district boundaries themselves compound the inequalities that our public schools were intended to conquer. In present day America, we allow invisible lines to determine the fate of our youngest and most vulnerable citizens. While many focus on policies that will bring more resources into these underserved districts, very few question why these lines exist in the first place. Our wealthy are consigning lower-income students to a lesser caste by cordoning off their wealth and hiding behind the notion of “local control”. We’ve created and maintained a system of schools segregated by class and bolstered by arbitrary borders that, in effect, serve as the new status quo for separate but unequal.