The '''Orthodox Church in America''' (OCA) is an [[autocephaly|autocephalous]] Church with parishes mainly in the United States and Canada (though with a few parishes also in Mexico, and until 2011 in Australia as well). The OCA traces its history to the Russian Orthodox missionary efforts in Alaska and the Aleutian Islands, which began in 1794. Originally an Alaskan diocese of the [[Church of Russia|Russian Orthodox Church]], it expanded to the contiguous United States (the "lower 48") from 1860 onwards. By the early 20th century, it had parishes throughout the United States (and some in Canada), mostly serving immigrant communities from Orthodox countries. Orthodox life in America was formerly known as severely disrupted by the Russian Revolution of 1917, leading the Russian Orthodox diocese to splinter into a number of separate jurisdictions organized mostly on ethnic grounds. The remaining core of the old diocese organized itself into a ''de facto'' self-governing Church in 1924, following the instructions of Patriarch [[Tikhon of Moscow]] who had directed all Russian Orthodox churches outside of Russia to govern themselves autonomously until regular communication could be resumed. This ''de facto'' self-governing Church in North America officially called itself the '''Russian Orthodox Greek Catholic Church in America''', or more and was informally, known as the '''Metropolia'''. Previous  In 1970, after having re-established communication with the Russian Orthodox Church, the American ''Metropolia'' received a ''[[tomos]]'' of [[autocephaly]] from Moscow, and changed its name to thatthe '''Orthodox Church in America'''. Since then, it was the North OCA has sought to cultivate an American Diocese identity, such as by promoting the use of local languages in the liturgy (mostly English, but also French, Spanish, Yupik and Aleut) and encouraging the veneration of [[Church List of RussiaAmerican Orthodox saints|Russian Orthodox ChurchAmerican saints]]. The OCA is in [[full communion]] with all of the other autocephalous Orthodox Churches, but its administrative status is disputed. Some other Churches recognize the OCA as autocephalous, but most regard it as a ''de jure'' part of the Russian Orthodox Church (although self-governing in practice). By number of parishes, the OCA is the largest Orthodox jurisdiction in North America. By number of members, it is second after the [[Greek Orthodox Archdiocese of America|Greek Archdiocese]].