This data set represents an updated Ecological Subsection Map for Northern Alaska. This 2012 revision focused on completing the incompletely mapped portion of the southern NPRA, improving mapping of glacial and outwash deposits within the Brooks Foothills, and improving consistency with existing surficial and bedrock geology maps in northern Alaska. The revisions resulted in 525 ecological subsections, nested within 55 ecosections and 12 ecoregions covering 411,781 km2. Attributes for the polygons include information on physiography, generalized geology, lithology, and referenced information sources. Description of attributes is provided in the map documentation report. The dataset can be downloaded from catalog.northslope.org.