The landmark now called Red Hill was known to the Native people as Katuktu, and the Spanish called it Cerrito de las Ranas, "little hill of frogs," for the many frogs living there. Mission San Juan Capistrano, founded on November 1, 1776, was the area's first permanent European settlement. In 1801 Spain granted 62,500 acres to Jose Antonio Yorba as Rancho San Antonio, which covered the land of today's Olive, Orange, Villa Park, Santa Ana, Tustin, Costa Mesa and Newport Beach, and smaller ranchos such as Rancho Santiago de Santa Ana later grew out of it.
More about Tustin
After the Mexican-American War American settlers arrived, and in 1868 Columbus Tustin, a carriage maker from Northern California, founded the town on 1,300 acres of the former Rancho Santiago de Santa Ana. Its townsite was bounded by Camino Real, Newport Avenue, First Street and what is now the Costa Mesa Freeway. Tustin was incorporated in 1927 with about 900 people.
During World War II the Navy built an antisubmarine airship base, later a Marine Corps helicopter station, on unincorporated land south of the city. Its two dirigible hangars were among the largest wooden structures ever built and are listed on the National Register of Historic Places, though the north hangar burned down in 2023. Postwar suburban growth brought annexations, including the former air station, and turned orchards and farmland into housing tracts and shopping centers.
Sources
Wikipedia: Tustin, California