The effects of subsurface heterogeneity on liquefaction phenomena during earthquakes are discussed using case histories and nonlinear dynamic analyses with different subsurface modeling approaches. The importance of geologic and anthropogenic controls and the effects of stratigraphic heterogeneity, lithological heterogeneity, and inherent soil variability at the project site scale are discussed. The results of these studies reinforce lessons regarding the importance of subsurface characterization and its representation in analyses for evaluating liquefaction-induced ground deformations and their impacts on civil infrastructure.