American income inequality across economic and geographic space, 1970–2010

• Unequal places contain 25% of the population and 13% of counties.
• Unequal places have better socioeconomic outcomes.
• Inequality is linked to high-wage finance and professional services.
• Equality associated with low-wage leisure and mid-wage education and health services.
• Inequality linked with mining and energy production, and fast declining agriculture.

This analysis examines the spatial clustering of income inequality and its socioeconomic correlates at the meso-scale over the past four decades. Cluster analysis is used to group N = 3078 counties into five inequality clusters; and multinomial logistic regression is used to assess the effects of socioeconomic correlates. High and extreme inequality places are concentrated in large metropolitan centers, high amenity rural areas, and parts of the Great Plains and Mountain West. They tend to have better socioeconomic outcomes, with fewer at-risk populations, higher incomes, lower poverty, and greater economic participation. Unequal places are more specialized in high-skill finance and professional services, and in energy-based mining. By contrast, equality places are associated with low-skill services, education and health services, manufacturing, and stable farm economies.