No one contests that Orthodoxy was brought to America by the Russians; and for many years there was but one Orthodox Church in America that cared for the faithful Orthodox that came here from many countries as well as for American converts. This jurisdiction was under the Russians.
Unfortunately, with the communist revolution in Russia, the Russian Church split in two: a church that compromised with the Bolsheviks and a church that refused compromise with the Bolsheviks.
The church in Russia is sometimes referred to as the Moscow Patriarchate, since its seeat is in Moscow; and is sometimes characterized as Sergian, a name derived from the first patriarch to officially compromise with the Bolsheviks – Sergius.
The Orthodox Church beyond the scope of the Bolshevik power did not compromise with the Bolsheviks. This included the church in America, and it eventually became known as the Russian Church Outside of Russia (ROCOR). The Orthodox churches in America that were ethnically Russian were under this jurisdiction until the late 1960s. At that time, most of these churches opted to come back under the jurisdiction of the Moscow Patriarchate.
Seeing this coming, ROCOR called a council, in which it declared an anathema against any that would do that. Here it is: An Explanation of History & Canonicity in the Orthodox Church.