The UNIS Hydrographic Database (UNIS HD) is a collection of temperature and salinity profiles from the area (0-34°E and 75-83°N). Main data contributors are The University Centre in Svalbard (UNIS), University of Bergen (UiB), Institute of Marine Research (IMR), Norwegian Polar Institute (NPI), the Arctic University of Norway (UiT), Institute of Oceanology Polish Academy of Sciences (IOPAS), The Scottish Association for Marine Science (SAMS), Arctic and Antarctic Research Institute (AARI), and Alfred Wegener Institut (AWI). Additional data in the database have been extracted from other data publishers; the Norwegian Marine Data Centre (NMDC, https://www.nmdc.no), the dataset catalogue of the Norwegian Polar Institute (https://data.npolar.no/dataset), the International Council for the Exploration of the Sea (ICES) dataset on ocean hydrography (https://ocean.ices.dk/HydChem), the PANGAEA data publisher (https://www.pangaea.de), the North Atlantic and Nordic Seas hydrography collection (NANSHY; Nilsen, 2015) based on the dataset from the project Norwegian Iceland Seas Experiment (NISE; Nilsen et al., 2008), and the Unified Database for Arctic and Subarctic Hydrography (UDASH; Behrendt et al., 2018). Data are processed with standard software from the instrument manufacturers, and most of them calibrated with in situ water bottle analysis and post-cruise calibration. However, calibration has not been quality checked in all the data, so use with caution (salinity values in particular). Duplicate data and outliers are removed. Remaining profiles are provided with information of owner or source institution and citation when possible (see Citation list).