In 1781 when Spanish settlers happened upon what was then a dry and dusty plain, they made friends with the natives. The area grew rapidly, though remained a practically undiscovered backwater, until the early 1800s.
The actual county of Los Angeles was established on 18 February 1850, by which time the area was under US jurisdiction, due to squabbling between the Spanish and Mexicans.
In 1913 the citizens of Los Angeles County approved a charter recommended by a board of freeholders which gave the County greater freedom to govern itself within the framework of state law, and today many residents feel, like Texas, that they're a law unto themselves.