Definition
Hypersegregation is the term sociologists Douglas Massey and Nancy Denton introduced in 1989 (and developed at length in American Apartheid, 1993) for U.S. metropolitan areas in which Black residents score in the highly segregated range on all five distinct geographic measures of segregation at once, rather than on just one or two.
A single high score might reflect any cause. Scoring high on all five — evenness, exposure, concentration, centralization, and clustering — describes a qualitatively different condition: a geographic isolation so multi-dimensional that a Black resident in a hypersegregated city is unlikely to encounter a non-Black neighbor, employer, school, retailer, or institution in the normal course of daily life.
Why it matters
How it works
Massey and Denton operationalized segregation along five geometric dimensions and set thresholds (typically 0.60 on a 0-to-1 scale) for "high" on each.
Evenness — the dissimilarity index
The share of either group that would have to move across census tracts to achieve uniform racial distribution across the metro. Chicago's Black-white dissimilarity around 1990 was roughly 0.85 — meaning 85 percent of Black or white residents would have to relocate for even distribution.
Exposure — the isolation index
The probability that a Black resident's tract-level neighbors are also Black. In a hypersegregated city, this can exceed 0.80, meaning the average Black resident lives in a tract that is 80+ percent Black.
Concentration
The geographic area occupied per capita. Hypersegregated cities pack their Black residents into a small fraction of the metro's total residential land, often in higher-density housing than the metro average.
Centralization
Proximity to the urban core. Hypersegregated cities locate Black residents disproportionately near downtown — a legacy of the migration-era settlement pattern and the urban-renewal-era refusal to permit dispersal.
Clustering
The degree to which Black tracts are contiguous to other Black tracts, forming one large ethnic zone rather than several scattered enclaves. High clustering means a Black resident can walk for miles without crossing the racial boundary.
A metro hits the threshold on all five only when each of the underlying processes (covenants, redlining, steering, public-housing siting, urban-renewal displacement, white flight) has run for decades. The pattern is durable: Chicago, Detroit, Cleveland, Milwaukee, and Newark were hypersegregated in 1990 and remained so in 2010 despite two decades of fair-housing enforcement.