This report disaggregates school racial composition at the district level in order to explore patterns of segregation affecting U.S. students. It examines segregation trends in large school districts nationwide, investigating whether metropolitan countywide districts are still integrated, the extent to which children in central city school districts are segregated from children of other races, and whether there are effects from the dramatic increase in minority enrollment in large suburban systems. The study analyzes enrollment data collected by the U.S. Department of Education in the NCES Common Core Data for the school year 2000-01, examining 239 districts with a total enrollment greater than 25,000. Virtually all districts showed lower levels of inter-racial exposure since 1986, suggesting a trend toward resegregation. Many of the districts experiencing the lowest levels of black-white exposure were also segregating in Hispanic exposure to whites. Districts showing the least resegregation in black-white exposure were mainly in the south. The lowest levels of black-white exposure were in districts with either no plan or where the courts rejected city-suburban plans. White students in over one-third of the districts had become more segregated from minority students. (Contains 17 tables.) (SM)