This collection provides electron number density values derived from features observed in plasma wave data obtained by the Cassini Radio and Plasma Wave Science (RPWS) instruments, along with observed or derived characteristic frequencies, and useful positional parameters for the spacecraft and related bodies. When present, frequency values of narrowband emissions at the upper hybrid resonance were digitized and combined with measured or model magnetic field to derive electron number density. At other times, features such as the upper cutoff in auroral hiss or electron plasma oscillations were used to determine the plasma frequency and electron density.