This dataset describes a sequence of tephra layers recovered from a Holocene sediment core taken at June Lake, California, USA. It includes tephra sediment stratigraphy, sample information, tephra layer thicknesses, tephra grain size data, volcanic glass geochemistry, Fe-Ti oxide geochemistry, SEM imagery, and method information. The tephra layers originate from the Mono-Inyo volcanic system. Most of this information is contained in a series of spreadsheets that follow tephra community recommended best practices. The listed files below follow the naming convention and format of Abbott et al. (2020) version 2.0, and they serve as worked examples of that format. See DOI: 10.5281/zenodo.3866266 for more information. June Lake Collection2b.xlsx (location information, sample information, stratigraphy) June Lake Sample_Processing.xlsx (sample preparation) June Lake Physical_analysis2b.xlsx (maximum grain size data, pumice class density) June Lake Physical_Microanalysis2.xlsx (SEM-EDS images, sample mount images) June Lake Geochemical_Analysis2.xlsx (EPMA method details) Glass and Fe-Ti oxide geochemistry by EPMA may be found in the following files: June Lake Glass DATA.xlsx June Lake Fe-Ti Oxides DATA.xlsx SEM and other images may be found in the following file: June Lake EPMA Images.zip