Claim: Plaza de César Chávez founded in 1797 is located in San Jose, California and has an area of 2.3-acre (9,000 m²).
Evidence: The Plaza de César Chávez is an urban plaza and park in Downtown San Jose, California, in Silicon Valley. The plaza's origins date to 1797 as the plaza mayor of the Spanish Pueblo de San José de Guadalupe, making it the oldest public space in Northern California. 2.3-acre (9,000 m²) 
1797 San Jose, California 2.3-acre (9,000 m²)