The Arc The Arc. of Jefferson & For people with intellectual and developmental disobilities Nearby Counties would like to thank the community for its support, especially all the Arc-members and non-member volunteers. Because of you, we continue to thrive. The Arc The Arc. of Jefferson & For people with intellectual and developmental disobilities Nearby Counties would like to thank the community for its support, especially all the Arc-members and non-member volunteers. Because of you, we continue to thrive.