X‐ray, neutron, and Raman scattering experiments have been performed on highly concentrated aqueous solutions of LiCl and ZnX2(X=Br and I) in the undercooled and glassy states as well as at room temperature. TheT1relaxation time and the self‐diffusion coefficient of the water protons in the aqueous the ZnBr2solutions have been measured at various temperatures toward the glass transition. For the concentrated LiCl solution, both X‐ray and neutron data have revealed stronger hydration of chloride ions (an increase in the hydration number and a decrease in the first neighbor Cl‐D distance) in the undercooled and glassy solutions than at ambient temperature. The X‐ray data have clearly shown the enhancement of the hydrogen bonded network of water in the undercooled and the glassy states. X‐ray and Raman data of the ZnX2solutions have demonstrated the formation of both [ZnX4]2−and [Zn(OH2)6]2+species in the undercooled and glassy solutions, in contrast to the presence of [ZnX2] and [ZnX3]−as main species at room temperature. The1H‐NMR data have revealed that the motion of water molecules in the ZnBr2solusions slows down with increasing solute concentration and lowering temperature. The translational motion of the water molecules is more retarded than the rotational motion with the decrease in temperature.