**Recovery Units** are special units of entities listed under the US Endangered Species Act that are geographically or otherwise identifiable and are essential to the recovery of the entire listed entity. Units are designated in recovery plans, and allow the agencies responsible for overseeing recovery under ESA - the U.S. Fish and Wildlife Service (FWS) and National Marine Fisheries Service (NMFS) - to split the range of a species into multiple units for recovery planning, rather than treating the species as a single entity. Because recovery units are defined as 'essential to the recovery of the entire listed entity', each recovery unit must be conserved to recover the species. Recovery actions and criteria may differ among units, allowing for more targeted and efficient recovery planning. Because the Services can delineate recovery units using a variety of factors – including genetic diversity, ecosystem diversity , and variation in threats – they can apply the tool to a wide range of taxa.