Residential segregation between blacks and whites persists in urban America. However, evidence from the 1990 Census suggests that peak segregation levels were reached in the past. We evaluate segregation patterns in 1990 and trends in segregation between 1980 and 1990 for the 232 U.S. metropolitan areas with substantial black populations. We review the historical forces that intensified segregation for much of the twentieth century, and identify key developments after 1960 that challenged institutionalized segregation. The results suggest that the modest declines in segregation observed during the 1970s continued through the 1980s. While segregation decreased in most metropolitan areas, the magnitude of these changes was uneven. Testing hypotheses developed from an ecological model, we find that the lowest segregation levels in 1990 and the largest percentage decreases in segregation scores between 1980 and 1990 occurred in young, southern and western metropolitan areas with significant recent housing construction. Because the black population continues to migrate to such areas, residential segregation between blacks and whites should decline further, but remain well above that for Hispanics or Asians.