The data comprises of dimensions of large wood pieces and the isotope composition (radiocarbon, stable carbon isotopes) of cellulose extracted from the wood samples. Large Wood (LW) samples were collected from the Mackenzie River delta region, Northwest Territories, Canada, in August 2019 and were analysed at the National Environmental Isotope Facility, UK. The scientific aims were to help constrain the source and age of wood carried by this large river system draining to the Arctic Ocean. Full details about this dataset can be found at https://doi.org/10.5285/19be1a45-c457-40af-a582-395257d7a3b0
