From values of the heat capacity of microcrystalline Ho(OH) 3 determined by precise adiabatic calorimetry from 11 to 350 K, the Schottky contribution associated with the Stark splitting of the ground J-manifold ( 5 I 8) was resolved by means of an extrapolation of the known lattice heat-capacity variation between La(OH) 3 and Gd(OH) 3. This calorimetrically deduced Schottky contribution is compared with that calculated from spectroscopically derived energy levels of Ho 3+ doped Y(OH) 3. Because the lattice parameters of Y(OH) 3 and Ho(OH) 3 are nearly identical it is assumed that the electronic energy levels of the Ho 3+ ions are the same in either host lattice. These results together with independent heat-capacity measurements made at lower temperatures were used to adjust the low-temperature thermophysical functions to evaluate C p R , S o R , and −[ “G o − H o (0)’ RT ] , at 298.15 K as 13.80, 15.64, and 7.855.