Portable X-ray fluorescence (pXRF) has been used to identify the geochemical source of lithic materials across North America, but comparatively few studies apply pXRF to compositional and geochemical sourcing studies of rock imagery pigments. Logan Simpson conducted in situ analyses using non-invasive pXRF to analyze the elemental composition of rock imagery pigments used to produce prehistoric pictographs at more than 20 rock art sites across Lincoln County, Nevada. The work was conducted as part of continuing research funded by the BLM Lincoln County Archaeological Initiative program. Standardized methods were developed in 2017 and 2018 and the methods helped establish a baseline methodology for future pXRF studies of rock art. In conjunction with previous research conducted in 2017 and 2018, the results from these new analyses were used to further evaluate the potential of this type of analysis to identify the minerals used in pigments; differentiate between pigment types; and detect the work of different artists, painting events, and re-touch episodes. GIS was also used to study the relationship between rock art sites and potential sources of pigments within Lincoln County.