Department of the Rappahannock
Its territory consisted of Virginia “east of the Blue Ridge and west of the Potomac River , the Fredericksburg and Richmond Railroad , including the District of Columbia and the country between the Potomac and the Patuxent Rivers . ” The commander of the I Corps , Irvin McDowell , was promoted to Major General and authorized to command the department . 
<triplet> District of Columbia <subj> Potomac River <obj> located in or next to body of water