Vast quantities of saline ground water await new commercial uses and economical demineralization processes for recognition as a valuable resource. Saline ground water is more widely distributed than any other natural resource, occurring throughout the United States and in geologic formations ranging from the oldest to the youngest. The Coastal Plain has the greatest reserve of fresh water in the country, but at depths ranging from a few feet to about 3,500 feet most of the fresh‐water aquifers also contain large quantities of brackish water. Paleozoic formations in the east‐central United States have long been producers of saline water as commercial brines and in association with oil and gas. The volume of saline ground water perhaps exceeds the fresh ground‐water supply in the Great Plains Region. The greater part of the Western Mountain Region is generally deficient in fresh ground water; however, saline water is present in highly permeable deposits in numerous closed basins and along saline streams. In each of these major ground‐water regions small to very large amounts of saline water can be pumped from wells ranging from a few tens of feet to several thousand feet in depth. Knowledge of saline water distribution is general and inadequate, having been attained as a by‐product of investigations of fresh‐water supplies. This knowledge should be expanded as technological advances in demineralization processes enhance the importance of saline water for potential supply in numerous water‐deficient areas.