More than 200 composition- and temperature-dependent viscosity datasets for binary systems involving ionic liquids are analyzed with the Arrhenius model to inspect the composition dependence of the Arrhenius fit parameters activation energy, E-a, and y-intercept, ln A. The analysis also includes a new viscosity dataset for the binary system 1-hexyl-3-methylimidazolium bis(trifluoromethylsulfonyl)amide-trichloromethane. The majority of the binary systems show linear dependence of E-a and ln A with mole fraction, either over the entire range of composition or over a wide range of compositions, typically between 0.2 < x(IL) < 1.0. These findings are useful for estimating unknown viscosities for binary systems involving ILs. As a side-outcome from the Arrhenius analysis and careful comparisons between datasets, a number of datasets are identified that are suspect of experimental inaccuracies.