The Central States Numismatic Society, founded in 1939, is one of the larger numismatic organizations in the United States with membership fluctuating around 2,000. CSNS, as it is known informally, operates in a 13 state Midwestern region but membership is open to residents of all states and foreign countries.

States in the region are Illinois, Indiana, Iowa, Kansas, Kentucky, Michigan, Minnesota, Missouri, Nebraska, North Dakota, Ohio, South Dakota and Wisconsin.