It is difficult to overstate the importance of segregation for race- and ethnicity-based school funding disparities in the United States. In many respects, unequal educational opportunity depends existentially on segregation. Racial and ethnic disparities in wealth accumulation are perpetuated over generations, ensuring persistent segregation even after explicitly racist housing discrimination was outlawed. This process has had serious and lasting implications for many important outcomes, including modern school funding equity. The mutually dependent relationship between economic and racial/ethnic segregation simultaneously depresses revenue and increases costs in racially isolated districts, creating a self-sustaining cycle of unequal opportunity and unequal outcomes. The descriptive analysis presented in this report examines this process, both nationally and with a focus on seven metropolitan areas: Baltimore (Maryland), the Bay Area (California), Birmingham (Alabama), Hartford (Connecticut), Kansas City (Kansas/Missouri), San Antonio (Texas), and the Twin Cities (Minnesota/Wisconsin).