Spartina patens (W. Aiton) G.H. Muhlenberg is a New World tropical-, subtropical-, and temperate-zone rhizomatous grass that often is a dominant species in coastal environments. It occurs in habitats ranging from foredunes to saturated soil conditions in high marshes and swales. Herein, we present a review of the extensive literature of this important species. Spartina patens occurs where salinity ranges from 1 to 27 ppt, but it will tolerate salinities up to 40 ppt for brief periods. It tolerates moderate tidal inundation, low nutrient levels, and low to moderate sand coverage. Also known as marshhay cordgrass, it may account for almost all net productivity in high marshes on the Gulf of Mexico coast of Louisiana. High marshes dominated by S. patens are affected by flooding depths associated with global warming and rising sea levels. It is a valuable species for coastal restoration projects for it quickly invades dredged material and storm washover sites. Spartina patens provides cover for wildlife and forage for livestock.