Is there a layer that shows the National Wetlands Inventory (NWI) data?

NWI data is available in the Content sub-tab under Overlays in a panel called Other Featured Data in the table of contents of The National Map viewer. NWI data layers are provided by the U.S. Fish & Wildlife Service (FWS) through their Wetlands ArcGIS Server REST service endpoint. To download Wetlands data, go to the FWS National Wetlands Inventory Web site.