Antarctic lakes represent highly sensitive recorders of polar environmental shifts. However, evaluating continent-scale geochemical baselines has been historically impeded by fragmented, localized data ( Heywood, 1972 ). This study presents a comprehensive synthesis of major ion chemistry from 4,457 water samples across 83 peer-reviewed publications to establish a unified hydrochemical framework. Major ion concentrations were harmonized and analyzed using compositional ratios and multivariate approaches to isolate dominant solute sources and geochemical control mechanisms. Across the continent, a dominant sodium-chloride signature emerges in coastal zones, with sodium-chloride molar ratios closely tracking seawater values (0.86), demonstrating a pervasive marine aerosol imprint. Conversely, inland isolated basins, particularly within the Continental Inland Ice-Free Valleys, exhibit profound geochemical modifications driven by the interplay of cryogenic concentration, intense sublimation, and localized rock-water interactions. Calcium-rich brines indicate advanced freeze-concentration cycles or localized carbonate leaching. By integrating these disparate datasets into a harmonized framework, this study clarifies the regional organization of Antarctic limnological systems and provides a crucial quantitative baseline for tracking future climate-driven variations in hydrologic fluxes, ice-free area expansions, and localized anthropogenic footprints.