The GPM Ground Validation DC-8 Camera Nadir GCPEx dataset contains geo-located, visible-wavelength imagery of the ground obtained from the nadir camera aboard the NASA DC-8 in Canada during the Cold-season Precipitation Experiment (GCPEx). GCPEx addressed shortcomings in the GPM snowfall retrieval algorithm by collecting microphysical properties, associated remote sensing observations, and coordinated model simulations of precipitating snow. These data sets were collected to aid in the achievement of the over arching goal of GCPEx which is to characterize the ability of multi-frequency active and passive microwave sensors to detect and estimate falling snow. The data is available only for February 20, 2012, a clear-air flight day. DC-8 Camera nadir data may be useful for determining snow cover and lake ice cover for emissivity studies. The dataset also includes, for convenience and reproducibility, aircraft navigation information and ground temperatures to aid in emissivity retrievals.