Wetland Classification Codes
The wetland classification codes are a series of letter and
number codes that have been developed to adapt the national
wetland classification system to map form. These
alpha-numeric codes correspond to the classification
nomenclature that best describes the habitat. (for example,
The Wetland Code Interpreter is a tool that will instantly provide the detailed habitat descriptions for an area represented by the wetland classification code. Enter a wetland area's code into the interpreter and obtain the classification of that wetland area as defined in Cowardin et al (1979).
Click here to open the Wetland Code Interpreter
- Wetlands and Deepwater Habitats Classification
Hierarchy - NWI Map Code Diagram (PDF) shows relationship of wetland
systems (e.g. estuarine), subsystems (e.g. intertidal), classes (e.g. emergent wetland) and subclasses (e.g. persistent).
- National Wetlands Classification Standard - The codes of wetland habitat types use the classification system in this Service publication: Classification of Wetlands and Deepwater Habitats of the United States 2nd Edition (1.4MB PDF), 2013, by Cowardin, Lewis M. et al.
- Classification of Wetlands and Deepwater Habitats of the United States 1st Edition (17MB PDF). Click here to view the HTML version of the 1st Edition.
- With the adoption of new Federal Wetlands Mapping Standards, the USFWS has developed an important companion document that describes the technical procedures and requirements for wetlands map data. The document entitled "Data Collection Requirements and Procedures for Mapping Wetland, Deepwater and Related Habitats of the United States (version 2)" (1.8MB PDF) is intended to aid organizations or individuals mapping wetlands and applying the Cowardin et al. classification system.
- NWI Water Regime Restriction Table (PDF)