This dataset contains supplementary data for the article “Differences in land-based mitigation estimates reconciled by separating natural and land-use CO2 fluxes at the country level”. The dataset includes gridded data and country-level estimates of land use, land-use change, and forestry (LULUCF) fluxes from bookkeeping models, gridded data and country-level estimates of the natural land sink, country-level estimates of LULUCF fluxes from UNFCCC reports, and country-level estimates of forest areas.