Sporobolus virginicus is a vigorous perennial grass that spreads through extensive, stiff, scaly rhizomes. The stems are erect, measuring 5-50(-90) dm long, and are freely branching, hollow, and glabrous. The leaves are simple and alternate, with harsh, usually involute blades ranging from 3 to 14 cm long and 2 to 5 mm wide. The leaf apex is acute, and the upper surfaces are ridged, sometimes featuring scattered papillose hairs. The veins are parallel. Leaf-sheaths are overlapping and glabrous, except for the pilose apex and upper margins, where hairs can be conspicuous and up to 3 mm long. The ligule is membranous, 0.2-0.4 mm long, and minutely and densely ciliate. Stipules are absent. The flowers are arranged in terminal, dense, cylindrical panicles 2 to 9 cm long and 0.3 to 1 cm in diameter. The panicle branches are short, erect, and densely flowered to the base. The spikelets are grayish or yellowish brown, glossy, appressed to the branches, laterally compressed, and measure 2-3.3 mm long. The first glume is lanceolate, 1.7-2.4 mm long, and 1-nerved with an acuminate apex. The second glume is ovate, 2-3.1 mm long, and 1-nerved with an acuminate apex. The lemmas are ovate, 1.9-2.5 mm long, and 1-nerved. The palea is as long as the lemma, often splitting between the nerves. The fruit is obovoid, measuring 0.9-1.2 mm long, with a thin ovary wall that gelatinizes. It is found on coastal dunes and other coastal sites, typically just above the high-tide mark around 0–15 meters.