Electrospray ionization-high-pressure mass spectrometry was used to determine the enthalpy, entropy, and Gibbs free energy for the equilibrium gas-phase ion-molecule association reactions of CmH2m+1NH3+ (m = 1-8), (CH3)(2)NH2+, and (CH3)(3)NH+ with one to three water ligands. A subset of these ions has been studied previously, and the thermochemical properties determined in this investigation compare favorably with the previously published results, providing validation of our experimental technique and method. In addition, the present measurements show that the addition of a water ligand to the monohydrated alkylammonium ion results in an increased stabilization in its structure and binding.