This article investigates the interfacial water structure of simple electrolyte solutions, challenging the traditional view that ions reside at the air/water interface. Using surface-specific heterodyne-detected vibrational sum-frequency generation (HD-VSFG) and neural network-assisted ab initio molecular dynamics (AIMD) simulations, the study reveals that ions in typical electrolyte solutions are located in a subsurface region, leading to a stratification of the interface into two distinct water layers. The outermost surface is ion-depleted, while the subsurface layer is ion-enriched. This surface stratification is crucial for understanding ion-induced water reorganization at the air/water interface. The research highlights that the distribution of ions at the air/water interface significantly influences the molecular structure of electrolyte solutions. This has important implications for atmospheric chemistry and climate science, as well as for understanding more complex interfaces involving electrodes, membranes, or minerals. The study challenges the conventional electric double layer (EDL) model, which assumes that ions create an electric field at the interface. Instead, the findings suggest that the interfacial structure is determined by the stratification of ions in a subsurface region, with the outermost surface being ion-depleted. The study analyzed ten electrolyte solutions, including HCl, NaOH, CsF, NaF, NaCl, NaBr, NaI, MgCl₂, Na₂SO₄, and MgSO₄. HD-VSFG spectra showed that the formation of an EDL cannot account for the observed spectra of sodium halide salts and other electrolytes, except for HCl and NaClO₄, where the hydrated proton and perchlorate have high surface propensity. The results indicate that subsurface ion enrichment dictates the interfacial aqueous structure, providing a more accurate understanding of typical electrolyte solutions. The study also demonstrates that the conventional classification of ions as 'surface enriched' or 'surface depleted' is only two limiting scenarios within a broader range of behaviors. The findings suggest that the interfacial structure is determined by the stratification of ions in a subsurface region, with the outermost surface being ion-depleted. This stratification model provides a more accurate understanding of the interfacial structure of typical electrolyte solutions and expands on current textbook descriptions, offering insights into the air/water interface puzzle and chemical reactivity at this interface.This article investigates the interfacial water structure of simple electrolyte solutions, challenging the traditional view that ions reside at the air/water interface. Using surface-specific heterodyne-detected vibrational sum-frequency generation (HD-VSFG) and neural network-assisted ab initio molecular dynamics (AIMD) simulations, the study reveals that ions in typical electrolyte solutions are located in a subsurface region, leading to a stratification of the interface into two distinct water layers. The outermost surface is ion-depleted, while the subsurface layer is ion-enriched. This surface stratification is crucial for understanding ion-induced water reorganization at the air/water interface. The research highlights that the distribution of ions at the air/water interface significantly influences the molecular structure of electrolyte solutions. This has important implications for atmospheric chemistry and climate science, as well as for understanding more complex interfaces involving electrodes, membranes, or minerals. The study challenges the conventional electric double layer (EDL) model, which assumes that ions create an electric field at the interface. Instead, the findings suggest that the interfacial structure is determined by the stratification of ions in a subsurface region, with the outermost surface being ion-depleted. The study analyzed ten electrolyte solutions, including HCl, NaOH, CsF, NaF, NaCl, NaBr, NaI, MgCl₂, Na₂SO₄, and MgSO₄. HD-VSFG spectra showed that the formation of an EDL cannot account for the observed spectra of sodium halide salts and other electrolytes, except for HCl and NaClO₄, where the hydrated proton and perchlorate have high surface propensity. The results indicate that subsurface ion enrichment dictates the interfacial aqueous structure, providing a more accurate understanding of typical electrolyte solutions. The study also demonstrates that the conventional classification of ions as 'surface enriched' or 'surface depleted' is only two limiting scenarios within a broader range of behaviors. The findings suggest that the interfacial structure is determined by the stratification of ions in a subsurface region, with the outermost surface being ion-depleted. This stratification model provides a more accurate understanding of the interfacial structure of typical electrolyte solutions and expands on current textbook descriptions, offering insights into the air/water interface puzzle and chemical reactivity at this interface.