Isopiestic results for SrCl2(aq) and BaCl2(aq) were obtained at T = 498 K and T = 523 K. As a check on previously reported results for MgCl2(aq) (from T = 383 K to T = 473 K), new isopiestic measurements were made over the temperature range from 383 K to 523 K. The new measurements are slightly different from our previous results. Here, NaCl(aq) was used as the reference electrolyte for computation of osmotic and activity coefficients. Our published model for the thermodynamic properties of CaCl2(aq) was used in a global least-squares treatment of the present results in combination with published results to provide comprehensive equations for the properties of these three electrolyte solutions. At elevated temperature, the available results consist primarily of excess Gibbs free energies (our isopiestic results), particularly for SrCl2(aq) and BaCl2(aq). Void regions in the temperature and pressure ranges of acceptable experimental results were estimated by reference to the properties of CaCl2(aq). Trends in the thermodynamic properties of aqueous solutions of the alkaline-earth metal chlorides were uniform at all temperatures and pressures used in the present work.