Reactions of 2-methyl-2-chloroadamantane (1) in a variety of pure and binary solvents have been studied at various temperatures and pressures up to 80 MPa. The sensitivity (m) to changes in solvent ionizing power of the Grunwald-Winstein equation, and the activation volume (${Delta}V^{ddag}$) are calculated from the specific rates. An excellent linear relationship (R = 0.997) for 1, log (k/$k_0$) = $0.80Y_{Cl}$ + 0.11, and the activation volume, ${Delta}V^{ddag}$ = -15.2 ~ -10.2 $mL{cdot}mol^{-1}$ were observed. These values are similar to those for solvolyses of 1-adamantyl halides over the full range of solvents, suggesting that the unimolecular mechanism involving ion pairs is rate-determining. These observations are also compared with those previously reported for the corresponding 1-adamantyl derivatives and chloroformate esters.