This paper presents densities and viscosities for n-butanol, 2-butanol, isobutanol, tert-butanol, and for binary mixtures with n-butanol as a common component at temperatures between (303.15 and 343.15) K over the entire composition range. The experimental apparatuses are a vibrating-tube densimeter for the density measurements and two Cannon-Fenske viscosimeters for the viscosity measurements. We have calculated excess molar volumes, dynamic viscosities, and excess Gibbs energy of activation from the experimental measurements. A temperature-dependent Redlich-Kister equation represents the calculated excess molar volumes, viscosity deviations, and excess Gibbs energy of activation. The Grunberg-Nissan equation has been used to correlate the experimental kinematic viscosities of the binary liquid mixtures.