Most of the archives and manuscript repositories in the United States fall into one of five broad categories: federal repositories, state archives, private manuscript libraries, corporate (profit and non-profit) archives, and college or university archives. Regional history research centers, a recent arrival on the archives scene, are a hybrid incorporating some aspect of all of the above categories. Although they comprise only a small portion of the archives field these regional centers have multiplied rapidly in the last two decades and the resources they now offer researchers are substantial. 1