Simultaneous measure of Thomson and Rayleigh light scattering were performed in order to determine electron density, electron temperature, and neutral density distributions in a hollow‐cathode arc. These measurements were performed in argon, nitrogen, helium, and hydrogen at approximately 1 Pa. The hollow‐cathode arc has also been studied in nitrogen and argon at high pressures ranging from 1–550 Pa. In this paper we present only high‐pressure data for nitrogen, although comparison with some results obtained in argon is provided. A plasma scrape‐off effect leads to a reduction in electron density in front of the anode and consequently to an enhancement of the anode fall. This enhancement was detected through an increase in electron temperature.