Frequently Asked Questions
About the Wetlands Data
The Get Data button on the Wetlands Mapper will open a new dialog box with options for downloading seamless wetlands data as viewed on the Wetlands Mapper. The Wetlands Mapper provides users enhanced access to the wetlands data with the capability to download geospatial wetland map data by state and watershed (HUC8) in shapefile and file geodatabase format; and to connect to the wetlands dataset via web services (WMS, KMZ and REST). Connecting to Web services allows users to dynamically interact with the data on their desktop and web-based applications. You can view the Shapefiles by using ESRI's ArcGIS Explorer free software among others. Geodatabases require a full ESRI ArcDesktop license.
By Watershed - The Download by Watershed option allows users to select individual watersheds in the mapper for data download. This tool gives you the option of downloading a Shapefile or File Geodatabase.
By State - You can also download data by State. Each State data download is available as either a compressed File Geodatabase or a Shapefile.
Web Services – Web Services option allows direct connection to the NWI web map service, for either wetlands data, wetlands status, or riparian data. For detailed information on how to connect to these services please visit our website at: https://www.fws.gov/wetlands/Data/Web-Map-Services.
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, PFO1A).
The Service provides extensive documentation of this Cowardin Classification System.
- The Wetlands and Deepwater Habitats Classification Hierarchy is a map code legend that shows the relationship of wetland systems (ex: estuarine), subsystems (ex: intertidal), and classes (ex: emergent wetland).
- Classification of Wetlands and Deepwater Habitats (2.1MB PDF) - outlines minimum requirements and guidelines for classifying wetlands and deepwater habitats consistent with the FGDC Wetlands Mapping Standard.
- NWI Map Code Diagram (1MB PDF) - wetlands and deepwater classification hierarchy table.
- Wetland Code Interpreter - provides detailed habitat descriptions as described by Cowardin et al (2013).
There are several download manager programs available, including some that are free. We use Xtreme Download Manager (Open Source software); it works really well.
Note: Due to their size, State files can not be sent by email.
About the Wetlands Mapper
The wetlands displayed on the Wetlands Mapper show wetland type and extent using a biological definition of wetlands. There is no attempt to define the limits of proprietary jurisdiction of any Federal, State, or local government, or to establish the geographical scope of the regulatory programs of government agencies.
Persons intending to engage in activities involving modifications within or adjacent to wetland areas should seek the advice of appropriate federal, state, or local agencies concerning specified agency regulatory programs and proprietary jurisdictions that may affect such activities.
For information about regulations that may affect wetlands or development on your property, contact the U.S. Army Corps of Engineers office nearest you: http://www.usace.army.mil/Locations.aspx.
This problem could be caused by old internet addresses in your browser and/or computer DNS cache. To clear both, please do the following in this order:
1. Open a Command Prompt window (Start button, Search box, type Command Prompt).
2. tyoe ipconfig /flushdns and press Enter. (if unsuccessful, you may have to do this with Admin rights).
3. Restart your computer.
4. Open your browser, then clear your cache memory.
5. Open the mapper from here: http://www.fws.gov/wetlands/data/Mapper.html
The Areas of Interest layer was designed to highlight wetlands that exhibit unique or important ecological characteristics. It currently includes sites located throughout the United States. It includes Wetlands of International Importance (Ramsar sites) as well as state natural areas, National Parks and National Wildlife Refuges. Each site is marked with a geographic location and includes a link to additional information about that particular wetland. Additional site and information may be added in the future.
For wetland digital data downloaded from our website:
U. S. Fish and Wildlife Service. Publication date (found in metadata). National Wetlands Inventory website. U.S. Department of the Interior, Fish and Wildlife Service, Washington, D.C. http://www.fws.gov/wetlands/
The Service's topical wetland and riparian maps are graphic representations of the type, size and location of the wetlands, deepwater or riparian habitats in the United States. These maps have been prepared from the analysis of high altitude imagery in conjunction with collateral data sources and field work.
The date a given wetland polygon is valid is based on the imagery that was used for the interpretation. This imagery information is visible when you click on a wetland polygon in the Wetlands Mapper. A display box containing information about the selected polygon will appear including 'Image Date(s)' which identifies the year(s) of imagery used. For a more general view of when the wetlands in a larger area were mapped display the' Data Source - Image Year' layer on the Wetlands Mapper.
The Print button allows users to print the current map view. Use the Panning and Zoom controls to center map to desired extent. After entering a title, selecting the print button will add the map to the print jobs queue.
Selecting an individual print job will open an Adobe PDF document with a rendition of the previously displayed map. The generated map will be approximately .5MB. The generated PDF document can be saved and/or printed.
There are several options for base maps including aerial and satellite imagery, street maps that show transportation routes, topographic maps provided by ESRI, and U.S. Geological Survey digital raster graphics of topographic mapping. Click on the desired base map type button to switch views. Please allow a few seconds for the view to refresh.
A list of Basemap contributors can be found at:
Metadata for this imagery service can be found at:
Historic wetlands data is available in IA, IN, WI, and portions of MN and SD, and more information about how this layer was developed and its suitability is available at https://www.fws.gov/wetlands/Data/Historic-Wetlands- Product-Summary.html.
The wetlands mapper also shows areas with available historic wetlands data, which will be included when downloading data by either state or watershed.
It is likely the base imagery date is different than the date of the imagery used for photointerpretation, and interim changes in the landscape since the wetland was mapped may result in mismatch when comparing newer imagery with ground conditions.
The wetlands mapper defaults to ESRI base imagery. More information can be found at:
Imagery can also be viewed in theESRI map viewer to determine image dates for specific areas of interest.
In addition, not all wetlands are wet throughout the year. Some wetlands may appear dry during certain times of the year while still supporting hydric soils and wetland plants characteristic of wetland areas.
Wetlands data is typically updated twice a year; in the spring and fall. The best way to check for updates is by using the projects mapper viewer link on the right of the main mapper page (http://www.fws.gov/wetlands/Data/Mapper.html), which shows recent data updates as well as active mapping projects.