Ecoregions of Yukon, 2014 is an update to the Yukon portion of the 1995 National Ecological Framework (NEF) described in Ecoregions of Yukon (Smith et al 2004). Because of people’s familiarity with the 1995 NEF, and its use in management and planning, these ecoregion revisions attempted to retain the 1995 divisions unless there were compelling reasons to change them. In Yukon there were several compelling reasons to revise the 1995 NEF: 1) capitalize on availability of digital inventory and knowledge and improve or adjust the 1995 mapping as necessary, 2) harmonize stratification along jurisdictional borders, 3) incorporate line work updates to the Soil Landscape polygons by Agriculture and AgriFood Canada (AAFC) happening concurrently, and 4) include Yukon revisions in a national update of NEF ecozones across Canada - led by Environment Canada (CCEA 2017). Mapping the ecoregions of Yukon is largely a top-down process and the divisional hierarchy is nested. The lowest level of the hierarchy is the Soil Landscapes of Canada unit (Soil Landscape Component, or SLC). SLCs are organized according to a uniform set of national soil and landscape criteria that are based on permanent natural attributes. SLCs polygons are not published in this release. Ecozones, ecoregions and ecodistricts are subdivisions at the continental scale of climatic zones; attention to physiography increases as map scale increases. There are many reasonable ways to distinguish Yukon ecoregions. Ecoregions are delineated principally on abiotic features, such as bedrock geology, glacial history and physiography, and so are relatively stable (i.e. enduring) over time. While considering changes to the 1995 NEF, the project team continued to recognize major physiographic and climatic distinctions. At the ecozone level the team included a stronger regional climate element and related the ecozone level to the bioclimate framework. The Ecoregions of Yukon concept is used for broad scale management applications. Its structure helps define ecologically relevant management units at various scales. The Ecoregions of the Yukon Territory (Smith et al. 2004) describes Yukon’s ecozones and ecoregions represented in the 1995 NEF (ESWG 1995). This reference continues to be a useful and relevant resource the Ecoregions of Yukon, 2014. For a fulsome treatment of the updates in the Ecoregions of Yukon, 2014 please refer to the report “Ecoregions of Yukon: Revisions to the Yukon portion of the National Ecological Framework.” (McKenna, K, J. Meikle and N. Flynn 2014).