Abstract | In 1923, Southern California produced over twenty percent of the world’s oil. At the epicenter of an oil boom from 1892 to the 1930s, Los Angeles grew into the nation’s fifth largest city. By the end of the rush, it had also become one of the most racially segregated cities in the country. Historians have overlooked the relationship between industrialists drilling for oil and real estate developers codifying a racist housing market, namely through “redlining” maps and mortgage lending. While redlining is typically understood as a problem of horizontal territory, this paper argues that the mapping of the underground—the location and volume of subterranean oil fields, in particular—was a crucial technique in underwriting urban apartheid. Mapping technologies linked oil exploitation with restrictive property rights, constructing oil as a resource and vertically engineering a racialized housing market. By focusing on petro-industrialization interlocked with segregationist housing, this article reveals an unexamined chapter in Los Angeles’s history of resource exploitation and racial capitalism. Moreover, it contributes to a growing literature on the social production of resources, extractive technology and political exclusion, and the technoscientific practices used by states and corporations to mine the underground while constructing metropolitan inequality above ground. |