A cienega or cienaga is a spring that is usually a wet, marshy area at the foot of a mountain, in a canyon, or on the edge of a grassland where groundwater bubbles to the surface. Often, a cienega does not drain into a stream, but evaporates, forming a small playa. The term cienega is used in English in the southwestern United States.
Ciénega or ciénaga is Spanish for "marsh" or "swamp."
Because evaporation usually causes the water to be alkaline, vegetation around a cienega commonly includes halophytes, including many unusual, rare, and endangered species of plants and animals. Notable among these is the monotypic genus Anemopsis, widely known in the southwestern United States as Yerba mansa.