Wetlands Data Layer

The Wetlands Data Layer is the product of over 45 years of work by the National Wetlands Inventory (NWI) and its collaborators and currently contains more than 35 million wetland and deepwater features. This dataset, covering the conterminous United States, Hawaii, Puerto Rico, the Virgin Islands, Guam, the major Northern Mariana Islands and Alaska, continues to grow at a rate of 50 to100 million acres annually as data are updated. The data layer is updated twice a year and these changes are reflected on the mapper and in the data downloads.

The NWI Program, in conjunction with federal and non-government agencies, developed standards for both wetland classification and mapping, which were adopted as federal standards by the Federal Geographic Data Committee (FGDC). As a result, all federally funded wetlands mapping projects must follow these standards, though state and private mapping projects are strongly encouraged to adopt the same guidance to foster a consistent national dataset. The NWI team provides technical support and guidance to facilitate standard compliant data submissions.

Data Access

The Wetlands Mapper is the public interface of the Wetlands Data Layer where users can view, query, download and print wetlands data and related resource information. Users can explore wetland and deepwater features throughout the Nation or in their specific area of interest. Pop-up windows provide access to wetland specific information and metadata, as well as related local, state, regional and national wetland documents. Data can be downloaded by state or watershed in several formats for use in maps and analysis. Web mapping services are also available so that GIS users and application developers can incorporate NWI data into their own desktop and web-based applications.