For more than 50 years, The Arc has been the leading advocate for Americans with cognitive, intellectual, and developmental disabilities. Founded as a grassroots organization to help individuals and families gain access to services and supports for loved ones with mental retardation, the organization has grown in size and scope to become the nation's largest volunteer-based organization serving the estimated 7.2 million Americans with mental retardation. Today, more than 800 local chapters and 41 state chapters provide direct services in communities across the county.