A collection of some 700 experimental D-region electron density profiles has been digitized and made easily computer accessible. By using these profiles the density at a given height has been determined and modeled as a function of solar zenith angle, sunspot number, latitude, season, and magnetic index. Expressions have been obtained for the density at heights from 55 to 90 km. It is found that the effects of the different parameters of the model vary with height. Magnetic effects, for example, are more important above 80 km, while latitude effects are most important at 60 km.