The crystal structure and the results of theoretical calculations for the new organoarsenate salt o-anisidinium dihydroarsenate (systematic name: 2-methoxyanilinium dihydrogen arsenate), C₇H₁₀NO⁺·H₂AsO₄ ⁻, are reported. The salt, crystallizing in the triclinic space group P\overline{1}, was synthesized using a solution method and was characterized by single-crystal X-ray diffraction analysis. It possesses a layered supramolecular architecture in the crystal. The intermolecular interactions were studied using Hirshfeld surface analysis which confirmed that hydrogen bonds and H...H contacts play dominant roles in the crystal structure of the investigated system. An analysis of the electronic structure and molecular modelling using charge distribution confirms the good electrophilic reactivity of the title compound.