The Arc of the United States is the largest national community-based organization with nearly 700 state and local federated chapters advocating for and serving people with intellectual and developmental disabilities (IDD) and their families. The Arc of the United States works on behalf of people with intellectual and developmental disabilities of all ages and with more than 100 different diagnoses, including autism, Down syndrome, Fragile X syndrome, and other developmental disabilities.
For people with intellectual and developmental disabilities