The purpose of this paper is to present a small manual with diagnostic keys, descriptions, habitats and distributions for the grasses of the Tidewater-Piedmont area. This area extends from the western shore of Chesapeake Bay to the eastern foothills of the Blue Ridge Mountains, and from the Pennsylvania-Maryland border, south to the Rappahannock and Rapidan rivers in northern Virginia. Within this region occur 191 established species and varieties of grasses. A few additional species occur as waifs and as adventives. It is hoped that this paper will be helpful to students and others interested in identifying grasses, and that it will encourage the further study and collection of grasses not only here but elsewhere.