Electron time-of-flight transient photocurrents from amorphous selenium (a-Se) films were examined over the range of temperatures and applied electric fields in order to deduce a consistent model for the distribution of localized states in the a-Se conduction band tail. Superimposed on an exponential tail with characteristic energy of 20meV, a Gaussian defect band around E−Ec=0.3eV controls the field-independent drift mobility, and a broad distribution of deeper electron traps is responsible for the significant emission currents that are observed for several decades of time after the transit time.