The Coastal and Marine Ecological Classification Standard (CMECS) is a catalog of terms and definitions that provides a means for classifying marine ecological units using a simple, standard format and common terminology. CMECS offers a way to organize and interpret data about the marine environment using a collection of settings (Aquatic and Biogeographic) and components (Biotic, Water Column, Substrate, and Geoform) in a semi-hierarchical framework.Endorsed by the FGDC in 2012, CMECS builds upon approaches from published national, regional, and local habitat classification procedures, and it offers an umbrella under which a national coastal and marine ecological classification can evolve. It is strongly recommended that federally funded projects working with environmental data in marine settings use CMECS as their primary classification system or include CMECS attributes for their data.The CMECS in Action project footprints feature layer shows the general locations of a growing collection of individual projects that have applied CMECS to categorize and describe observational data, define aquatic biotopes, and identify and inventory benthic habitat.Share your project with us so we can share it with others! Email ocm.cmecs-ig@noaa.gov with your project information.More information about CMECS, including technical guidance and examples of how to apply CMECS is available on the NOAA Integrated Ocean and Coastal Mapping Coordination Team’s website.