Elastic scattering cross sections for the interaction of 100-MeV protons with 6Li, 7Li, 9Be, and 12C have been analyzed using the optical model. The experimental differential cross sections are reasonably reproduced. It has been found that no average set of geometrical parameters can provide a quantitative fit to the experimental data for all of these light nuclei; they must be treated individually, with optimum optical potential parameters fluctuating from one nucleus to another. Other features revealed in this analysis include: (1) the spin–orbit radius parameter is smaller than those of the real and imaginary parts of the potential, (2) surface and volume absorption potentials give equally good fit to the experimental results, (3) the radius parameters of the real and imaginary potentials differed from each other, and (4) the radius parameter of the real part of the potential is larger than those used for heavy nuclei.