Aliso Viejo is a city in Orange County, California. It had a population of 47,823 as of the 2010 census, up from 40,166 as of the 2000 census. It became Orange County’s 34th city on July 1, 2001, the only city in Orange County to be incorporated since 2000. It is bordered by the cities of Laguna Beach on the west and southwest, Laguna Hills on the east, Laguna Niguel on the southeast, and Laguna Woods on the north.
Aliso Viejo had been an unincorporated community since around 1990, and incorporated as a city in 2001 due to the efforts of the Aliso Viejo Cityhood 2000 Committee, which was responsible for introducing an initiative on the ballot for the 2001 special election. Voters passed the initiative with 93.3% in favor of incorporation. Carmen Vali-Cave, the co-founder and president of the Committee, became the new city’s first mayor.