Watts did not become predominantly black until the 1940s, as the
Second Great Migration brought tens of thousands of migrants, mostly
from Louisiana, Mississippi, Arkansas, and Texas, who left segregated
Southern states in search of better opportunities in California.
During World War II, the city built several large housing projects
(including Nickerson Gardens, Jordan Downs, and Imperial Courts) for
the thousands of new workers in war industries. By the early 1960s,
these projects had become nearly 100 percent black, as whites moved on
to new suburbs outside the central city. As industrial jobs
disappeared from the area, the projects housed many more poor families
than they had traditionally.

Longstanding resentment by Los Angeles's working-class black community
over discriminatory treatment by police and inadequate public services
(especially schools and hospitals) exploded on August 11, 1965, into
what were commonly known as the Watts Riots. The event that
precipitated the disturbances, the arrest of a black youth by the
California Highway Patrol on drunk-driving charges, actually occurred
outside Watts. Mobs did the most property damage in Watts in the
turmoil.