The Episcopal Church is a U.S.-based member province of the worldwide Anglican Communion, a global association of 30 autonomous Anglican churches. All members of the Anglican Communion are bound by similar liturgies that are based on the Book of Common Prayer.
The Anglican Communion is massive, encompassing more than 70 million members (called Episcopalians) in 164 countries. It’s the third largest body of Christians in the world, behind only the Roman Catholic and Eastern Orthodox traditions.
The Episcopal Church itself has between two and three million members and encompasses 100 dioceses in the U.S., plus another 11 dioceses in other countries and U.S. territories. In Europe, the two dioceses are part of the Convocation of Episcopal Churches in Europe.