Ciénegas, as defined here, are wetlands in arid and semi-arid regions associated with groundwater or lotic components that ideally result in perennial waters on temporal scales of decades to centuries. Ciénegas are typically no lower than 0 m, and higher than 2000 m, rarely lower but sometimes higher elevation localities occur. Ciénegas are typified by significant differences in flora and fauna relative to the greater terrestrial conditions in the region in which it is located. Ciénegas are freshwater to brackish North American wetlands associated with fluvial systems of arid/semi-arid areas of the southwestern U.S. and northwestern Mexico. Once extensively utilized by the region's indigenous human cultures, early European explorers and settlers, the extent of these aquatic riparian communities has dramatically decreased from historic conditions and the community is now considered imperiled in North America. This dataset provides location information and some limited attributes of ciénegas in the southwestern U.S. and northern Mexico. There is no information as to the size of the ciénega and other important attributes.