The Greek Catholic Union of the USA is the oldest continuous fraternal benefit society for Rusyn immigrants and their descendants in the United States.
Founded as the Greek Catholic Union of Rusyn Brotherhoods in the USA (GCU) in Wilkes-Barre, Pennsylvania on 14 February 1892, it was headquartered for most of the 20th century in the heart of Pittsburgh, Pennsylvania's steel valley in Homestead. In 1987 it moved to a large tract of land in suburban Pittsburgh near Beaver.
The original goals of the organization were to unite Greek Catholics in America who spoke the Rusyn language; to provide insurance for its members; and to encourage education. Its flagship publication was Amerikansky Russky Viestnik.
GCU was active politically in the early twentieth century, especially in securing a place for Rusyns in the new nation of Czechoslovakia. Also GCU consistently opposed the notion that Rusyns are Ukrainians, arguing instead that they are a distinct nationality. GCU membership peaked in the 1920s at over 130,000 in more than 1,000 lodges throughout the United States.
In the 21st century, when Rusyn Americans are well integrated into American society, GCU operates largely as an insurance organization with assets of over $500 million. It also manages Seven Oaks Country Club and a housing development community on its estate.