Santa Ana (sănˈtə ănˈə) [key], city (1990 pop. 293,742), seat of Orange co., S Calif., in the fertile Santa Ana valley; inc. 1886. It began as a farm trade and processing center for the surrounding region and was connected to Los Angeles in 1878 by the Southern Pacific RR. Santa Ana grew industrially after World War II. There is diverse manufacturing in the city, which is part of the large Anaheim–Santa Ana–Garden Grove metropolitan area. Insurance companies are also major employers. During the late 20th cent. Santa Ana was one of the fastest-growing U.S. cities. The Bowers Museum of Cultural Art and the Mexican American Museum of Art are there.