This chapter provides an overview of ion chromatography columns including the early history of ion chromatography columns and the state-of-the-art concerning the architecture of ion chromatography columns. Ion chromatography is a highly specialized branch of liquid chromatography, generally making use of columns specifically designed for ion chromatography and intended to be used with ion chromatography instrumentation. In general, ion chromatography is performed with a specialized pumping system designed for the delivery of highly acidic and highly basic mobile phases without risk of corrosion as a consequence of the extreme pH associated with such mobile phases. The earliest phases in ion chromatography were based on cross-linked polystyrene since they provided the necessary chemical stability to withstand long-term exposure to mineral acids. One disadvantage of using sulfonated cation-exchange materials for ion chromatography arises from the high-affinity such materials have for divalent cations.