This dataset is used for figures in the paper "Seasonal and dust related variations of the dayside thermospheric and ionospheric compositions of Mars observed by MAVEN/NGIMS." The dataset contains neutral and ion number densities measured by MAVEN/NGIMS and estimated ion number densities under the photochemical equilibrium (PCE). The electron temperature measured by MAVEN/LPW and the photoionization rates estimated by the EUVAC solar flux model (Richards et al., 1994), which are used for estimation of ion number densities under the PCE, are included in the dataset. Detailed information can be found in the readme files in each directory.