Mission Viejo /ˈmɪʃən viːˈeɪhoʊ/ is an affluent city located in southern Orange County, California, U.S. in the Saddleback Valley. Mission Viejo is considered one of the largest master-planned communities ever built under a single project in the United States, and is rivaled only by Highlands Ranch, Colorado, in its size. Its population as of 2014 was estimated at 96,346.
Mission Viejo is suburban in nature and culture. The city is mainly residential, although there are a number of offices and businesses within its city limits. The city is known for its picturesque tree-lined neighborhoods, receiving recognition from the National Arbor Day Foundation. The city's name is a reference to Rancho Mission Viejo, a large Spanish land grant from which the community was founded.
Mission Viejo was named the safest city in the United States by the Morgan Quitno crime statistic survey (compiled from FBI data). The city was also ranked safest in California and third in the nation by CQ Press.