Libraries often have both physical collections and digital collections. Consider university and colleges, public libraries (which include county and state libraries) as well as special libraries (such as music libraries, law libraries, and medical libraries).
A repository is place where specific type of information is housed, usually by an institution. In this case, the information focuses on Appalachia. Online or in-person.
An archive houses primary sources, which are first-hand accounts. Online or in-person.
A digital library contains ONLY resources that have been digitized or made available online.