Geochemical and mineralogical data were collected for samples of the Devonian Marcellus Shale, as well as overlying and underlying units in the Enerplus Snow Shoe 4-8HG core. The data was integrated with well logs in a manuscript that focuses on the estimation of original organic richness (total organic carbon content) in thermally mature petroleum source rocks. This data release contains data generated by USGS laboratories or contract laboratories using USGS methods and quality control processes. Core photos and other datasets collected on this core can be accessed at the USGS Core Research Center’s website under library number V065 (https://my.usgs.gov/crcwc/core/report/135378).