Yorba Linda (yôrˈbə lĭnˈdə) [key], city (1990 pop. 52,422), Orange co., S Calif., in a region of citrus fruit; inc. 1967. The city grew tremendously in the late 20th cent. along with the southern California area. There is food processing and the production of machinery, semiconductors, aircraft parts, plastics, and electromedical apparatus. Yorba Linda is the birthplace of former President Richard M. Nixon.