The Arc of California is the state affiliate of The Arc of the United States. The Arc of the United States is the national organization of and for people with mental retardation and related developmental disabilities and their families. It is devoted to promoting and improving supports and services for people with mental retardation and their families. The association also fosters research and education regarding the prevention of mental retardation in infants and young children. Local chapters of the Arc of California are listed on this site.