When was the first city in California established?

From 1697 to 1777, the capital of Las Califorias (The Californias), which included that area that is now the U. S. state of California, was Loreto, which is located in what is now the Mexican state of Baja California Sur.

When Alta California (Upper California) became a separate Spanish territory, its capital was Monterey. That was the situation at the time that Mexico won independence from Spain in 1821.

When The California Republic declared independence from Mexico in 1846, Sonoma was its capital.

The first capital of the U. S. State of California was San Jose (1850-1851).