Deschampsia elongata is a species of grass known by the common name slender hairgrass. It is native to western North America from Alaska to Wyoming to northern Mexico, and South America in Chile. It grows at all elevations, often in moist areas. It is a perennial grass forming dense clumps sometimes exceeding a meter in height. Most of the leaves are located in a tuft about the base of the stems. The inflorescence is a thin row of V-shaped spikelets arranged parallel to and mostly flat against the stem.