The National Permafrost Database contains data on permafrost thermal regime and permafrost thickness, and active layer characteristics in Canada. The data have been measured and/or compiled by the GSC over the last 30 years, as both published and unpublished databases. Site attributes include: type of observation (shallow or deep), status of measurement program (active monitoring or inactive), active layer depth, permafrost temperature data, permafrost thickness, other site or material characteristics, responsible agency, and published references. The data are relevant to many clients and stakeholders involved in: northern exploration, development and infrastructure design, land use, environmental assessment, the detection of the terrestrial climate signal and of its spatial variability in permafrost regions, the assessment of the impacts of climate change on permafrost, and testing and improving cryospheric and general circulation models. The database includes a number of active monitoring sites which contribute to the Global Terrestrial Network for Permafrost (GTNet-P), through the international CALM (Circumpolar Active Layer Monitoring) program, and a new global borehole temperature monitoring program. Canadian permafrost baseline data and monitoring activities contribute to GCOS (Global Climate Observation System) climate change programs of the World Meteorological Organizaton.