US Army Center for Military History

“ Every volunteer regiment, by law, contained at least one Regular Army officer who normally held a volunteer commission one or more grades above his lineal rank in the Regular Army. Such officers normally were selected either because they were native sons of the specific state or because they were serving as Regular Army advisors with the state or teaching in a state's college or university system when war broke out. ”

“ United States Volunteers were a special category, being raised exclusively under Federal sponsorship as a temporary wartime augmentation to the Regular Army. A few of these units (most notably the 1st United States Volunteer Cavalry ["Rough Riders"] ) incorporated prewar militia companies. Original muster rolls and all official documents generated during active Federal service remained the property of the United States Army and are now in the custody of the National Archives and Records Administration. ”

“ Personal papers are most often found in state archives and historical societies, private university archives, local historical societies and libraries, or in the collections of the US Army Military History Institute, Carlisle Barracks, Pennsylvania. ”