Rancho La Brea was a 4,439-acre (17.96 km2) Mexican land grant in present-day Los Angeles County, California, given in 1828 to Antonio Jose Rocha and Nemisio Dominguez by José Antonio Carrillo, the alcalde of Los Angeles.

[5] With the cession of California to the United States after the Mexican–American War, the 1848 Treaty of Guadalupe Hidalgo provided that the land grants would be honored.

[6][7] As a lawyer and surveyor, Henry Hancock worked for the Rocha family to aid them with their efforts to prove their claim to Rancho La Brea.

[10][11] Hancock paid $20,000 for the Mexican grants (at $2 or $3 per acre) with his profits from the sale of gold he had found in a rich placer mine.

[13] Most of Rancho La Brea was later subdivided and developed by his surviving son, Captain George Allan Hancock.