USA Flood Hazard Areas

The Federal Emergency Management Agency (FEMA) produces Flood Insurance Rate maps and identifies Special Flood Hazard Areas as part of the National Flood Insurance Program's floodplain management. Special Flood Hazard Areas have regulations that include the mandatory purchase of flood insurance.
Dataset Summary
Phenomenon Mapped: Flood Hazard Areas Coordinate System: Web Mercator Auxiliary Sphere Extent: 50 United States plus Puerto Rico, the US Virgin Islands, Guam, the Northern Mariana Islands and American Samoa Visible Scale: The layer is limited to scales of 1:1,000,000 and larger. Use the USA Flood Hazard Areas imagery layer for smaller scales. Source: Federal Emergency Management Agency Publication Date: April 1, 2019
This layer is derived from the April 1, 2019 version of the National Flood Hazard Layer feature class S_Fld_Haz_Ar. The data were aggregated into eight classes to produce the Esri Symbology field based on symbology provided by FEMA. All other layer attributes are derived from the National Flood Hazard Layer. The layer was projected to Web Mercator Auxiliary Sphere and the resolution set to 1 meter.
To improve performance Flood Zone values "Area Not Included", "Open Water", "D", "NP", and No Data were removed from the layer. Areas with Flood Zone value "X" subtype "Area of Minimal Flood Hazard" were also removed. An imagery layer created from this dataset provides access to the full set of records in the National Flood Hazard Layer.
A web map featuring this layer is available for you to use.
What can you do with this Feature Layer?
Feature layers work throughout the ArcGIS system. Generally your work flow with feature layers will begin in ArcGIS Online or ArcGIS Pro. Below are just a few of the things you can do with a feature service in Online and Pro.
ArcGIS Online
  • Add this layer to a map in the map viewer. The layer is limited to scales of approximately 1:1,000,000 or larger but an imagery layer created from the same data can be used at smaller scales to produce a webmap that displays across the full range of scales. The layer or a map containing it can be used in an application.
  • Change the layer’s transparency and set its visibility range
  • Open the layer’s attribute table and make selections and apply filters. Selections made in the map or table are reflected in the other. Center on selection allows you to zoom to features selected in the map or table and show selected records allows you to view the selected records in the table.
  • Change the layer’s style and filter the data. For example, you could change the symbology field to Special Flood Hazard Area and set a filter for = “T” to create a map of only the special flood hazard areas. 
  • Add labels and set their properties
  • Customize the pop-up
ArcGIS Pro
  • Add this layer to a 2d or 3d map. The same scale limit as Online applies in Pro
  • Use as an input to geoprocessing. For example, copy features allows you to select then export portions of the data to a new feature class. Areas up to 1,000-2,000 features can be exported successfully.
  • Change the symbology and the attribute field used to symbolize the data
  • Open table and make interactive selections with the map
  • Modify the pop-ups
  • Apply Definition Queries to create sub-sets of the layer
This layer is part of the Living Atlas of the World that provides an easy way to explore the landscape layers and many other beautiful and authoritative maps on hundreds of topics.

Data and Resources

Field Value
dcat_issued 2020-07-10T23:11:15.000Z
dcat_modified 2020-07-14T16:36:24.000Z
dcat_publisher_name CA Governor's Office of Emergency Services
encoding utf8
guid https://gis-calema.opendata.arcgis.com/datasets/527151eb840d46f3aa5dcfa5ac13d561_0
spatial {"type": "Polygon", "coordinates": [[[-170.8484, -14.3752], [-170.8484, 66.5916], [145.8322, 66.5916], [145.8322, -14.3752], [-170.8484, -14.3752]]]}
Groups
  • NSF
  • United States
Tags
  • Basedata
  • Data Library
  • Esri
  • Flood
  • NSF
  • USA Flood Hazard
  • United States
isopen False
license_id CC0-1.0
license_title CC0-1.0
metadata_created 2026-10-30T17:04:53.752187
metadata_modified 2026-10-30T17:04:53.752192
notes <div style='font-family: &quot;Avenir Next W01&quot;, &quot;Avenir Next W00&quot;, &quot;Avenir Next&quot;, Avenir, &quot;Helvetica Neue&quot;, sans-serif; font-size: 16px; margin: 0px; padding: 0px;'>The <a href='https://www.fema.gov/' rel='nofollow ugc' style='color: rgb(0, 121, 193); text-decoration-line: none; font-family: inherit;' target='_blank'>Federal Emergency Management Agency</a> (FEMA) produces <a href='https://www.fema.gov/flood-insurance-rate-map-firm' rel='nofollow ugc' style='color: rgb(0, 121, 193); text-decoration-line: none; font-family: inherit;' target='_blank'>Flood Insurance Rate maps</a> and identifies <a href='https://www.fema.gov/special-flood-hazard-area' rel='nofollow ugc' style='color: rgb(0, 121, 193); text-decoration-line: none; font-family: inherit;' target='_blank'>Special Flood Hazard Areas</a> as part of the <a href='https://www.fema.gov/national-flood-insurance-program' rel='nofollow ugc' style='color: rgb(0, 121, 193); text-decoration-line: none; font-family: inherit;' target='_blank'>National Flood Insurance Program's</a> floodplain management. Special Flood Hazard Areas have regulations that include the mandatory purchase of flood insurance.</div><div style='font-family: &quot;Avenir Next W01&quot;, &quot;Avenir Next W00&quot;, &quot;Avenir Next&quot;, Avenir, &quot;Helvetica Neue&quot;, sans-serif; font-size: 16px; margin: 0px; padding: 0px;'><br /></div><div style='font-family: &quot;Avenir Next W01&quot;, &quot;Avenir Next W00&quot;, &quot;Avenir Next&quot;, Avenir, &quot;Helvetica Neue&quot;, sans-serif; font-size: 16px; margin: 0px; padding: 0px;'><font size='4' style='font-family: inherit;'>Dataset Summary</font></div><div style='font-family: &quot;Avenir Next W01&quot;, &quot;Avenir Next W00&quot;, &quot;Avenir Next&quot;, Avenir, &quot;Helvetica Neue&quot;, sans-serif; font-size: 16px; margin: 0px; padding: 0px;'><font size='4' style='font-family: inherit;'><br /></font></div><div style='font-family: &quot;Avenir Next W01&quot;, &quot;Avenir Next W00&quot;, &quot;Avenir Next&quot;, Avenir, &quot;Helvetica Neue&quot;, sans-serif; font-size: 16px; margin: 0px; padding: 0px;'><div style='font-family: inherit; margin: 0px; padding: 0px;'><b>Phenomenon Mapped: </b>Flood Hazard Areas</div><div style='font-family: inherit; margin: 0px; padding: 0px;'><b>Coordinate System: </b>Web Mercator Auxiliary Sphere</div><div style='font-family: inherit; margin: 0px; padding: 0px;'><b>Extent: </b>50 United States plus Puerto Rico, the US Virgin Islands, Guam, the Northern Mariana Islands and American Samoa</div><div style='font-family: inherit; margin: 0px; padding: 0px;'><b>Visible Scale: </b>The layer is limited to scales of 1:1,000,000 and larger. Use the <a href='https://www.arcgis.com/home/item.html?id=11955f1b47ec41a3af86650824e0c634' rel='nofollow ugc' style='color: rgb(0, 121, 193); text-decoration-line: none; font-family: inherit;' target='_blank'>USA Flood Hazard Areas imagery layer</a> for smaller scales.</div><div style='font-family: inherit; margin: 0px; padding: 0px;'><b>Source:</b> <a href='https://www.fema.gov/' rel='nofollow ugc' style='color: rgb(0, 121, 193); text-decoration-line: none; font-family: inherit;' target='_blank'>Federal Emergency Management Agency</a></div><div style='font-family: inherit; margin: 0px; padding: 0px;'><b>Publication Date:</b> April 1, 2019</div><div style='font-family: inherit; margin: 0px; padding: 0px;'><div style='font-family: inherit; margin: 0px; padding: 0px;'><br /></div><div style='font-family: inherit; margin: 0px; padding: 0px;'>This layer is derived from the April 1, 2019 version of the <a href='https://www.fema.gov/national-flood-hazard-layer-nfhl' rel='nofollow ugc' style='color: rgb(0, 121, 193); text-decoration-line: none; font-family: inherit;' target='_blank'>National Flood Hazard Layer</a> feature class S_Fld_Haz_Ar. The data were aggregated into eight classes to produce the Esri Symbology field based on symbology provided by FEMA. All other layer attributes are derived from the National Flood Hazard Layer. The layer was projected to Web Mercator Auxiliary Sphere and the resolution set to 1 meter.</div><div style='font-family: inherit; margin: 0px; padding: 0px;'><br /></div><div style='font-family: inherit; margin: 0px; padding: 0px;'>To improve performance Flood Zone values &quot;Area Not Included&quot;, &quot;Open Water&quot;, &quot;D&quot;, &quot;NP&quot;, and No Data were removed from the layer. Areas with Flood Zone value &quot;X&quot; subtype &quot;Area of Minimal Flood Hazard&quot; were also removed. An <a href='https://www.arcgis.com/home/item.html?id=11955f1b47ec41a3af86650824e0c634' rel='nofollow ugc' style='color: rgb(0, 121, 193); text-decoration-line: none; font-family: inherit;' target='_blank'>imagery layer created from this dataset</a> provides access to the full set of records in the National Flood Hazard Layer.</div><div style='font-family: inherit; margin: 0px; padding: 0px;'><br /></div><div style='font-family: inherit; margin: 0px; padding: 0px;'>A <a href='https://www.arcgis.com/home/item.html?id=fedc7c080e7f434186e0e623e0062c5b' rel='nofollow ugc' style='color: rgb(0, 121, 193); text-decoration-line: none; font-family: inherit;' target='_blank'>web map featuring this layer</a> is available for you to use.</div><div style='font-family: inherit; margin: 0px; padding: 0px;'><br /></div></div><div style='font-family: inherit; margin: 0px; padding: 0px;'><div style='font-family: inherit; margin: 0px; padding: 0px;'><font size='4' style='font-family: inherit;'>What can you do with this Feature Layer?</font></div><div style='font-family: inherit; margin: 0px; padding: 0px;'><font size='4' style='font-family: inherit;'><br /></font></div><div style='font-family: inherit; margin: 0px; padding: 0px;'>Feature layers work throughout the ArcGIS system. Generally your work flow with feature layers will begin in ArcGIS Online or ArcGIS Pro. Below are just a few of the things you can do with a feature service in Online and Pro.</div><div style='font-family: inherit; margin: 0px; padding: 0px;'><br /></div><div style='font-family: inherit; margin: 0px; padding: 0px;'><b>ArcGIS Online</b></div><div style='font-family: inherit; margin: 0px; padding: 0px;'><ul><li>Add this layer to a map in the map viewer. The layer is limited to scales of approximately 1:1,000,000 or larger but an <a href='https://www.arcgis.com/home/item.html?id=11955f1b47ec41a3af86650824e0c634' rel='nofollow ugc' style='color: rgb(0, 121, 193); text-decoration-line: none; font-family: inherit;' target='_blank'>imagery layer</a> created from the same data can be used at smaller scales to produce a <a href='https://www.arcgis.com/home/item.html?id=fedc7c080e7f434186e0e623e0062c5b' rel='nofollow ugc' style='color: rgb(0, 121, 193); text-decoration-line: none; font-family: inherit;' target='_blank'>webmap</a> that displays across the full range of scales. The layer or a map containing it can be used in an application.</li></ul></div><div style='font-family: inherit; margin: 0px; padding: 0px;'><ul><li>Change the layer’s transparency and set its visibility range</li></ul><ul><li>Open the layer’s attribute table and make selections and apply filters. Selections made in the map or table are reflected in the other. Center on selection allows you to zoom to features selected in the map or table and show selected records allows you to view the selected records in the table.</li></ul><ul><li>Change the layer’s style and filter the data. For example, you could change the symbology field to Special Flood Hazard Area and set a filter for = “T” to create a map of only the special flood hazard areas. </li></ul><ul><li>Add labels and set their properties</li></ul><ul><li>Customize the pop-up</li></ul><ul><li>Use in <a href='https://doc.arcgis.com/en/arcgis-online/analyze/use-analysis-tools.htm' rel='nofollow ugc' style='color: rgb(0, 121, 193); text-decoration-line: none; font-family: inherit;' target='_blank'>analysis tools</a> to discover patterns in the data</li></ul></div><div style='font-family: inherit; margin: 0px; padding: 0px;'><b>ArcGIS Pro</b></div><div style='font-family: inherit; margin: 0px; padding: 0px;'><ul><li>Add this layer to a 2d or 3d map. The same scale limit as Online applies in Pro</li></ul><ul><li>Use as an input to geoprocessing. For example, copy features allows you to select then export portions of the data to a new feature class. Areas up to 1,000-2,000 features can be exported successfully.</li></ul><ul><li>Change the symbology and the attribute field used to symbolize the data</li></ul><ul><li>Open table and make interactive selections with the map</li></ul><ul><li>Modify the pop-ups</li></ul><ul><li>Apply Definition Queries to create sub-sets of the layer</li></ul></div></div><div style='font-family: inherit; margin: 0px; padding: 0px;'><div style='font-family: inherit; margin: 0px; padding: 0px;'>This layer is part of the <a href='https://livingatlas.arcgis.com/' rel='nofollow ugc' style='color: rgb(0, 121, 193); text-decoration-line: none; font-family: inherit;' target='_blank'>Living Atlas of the World</a> that provides an easy way to explore the landscape layers and many other beautiful and authoritative maps on hundreds of topics.</div></div></div>
num_resources 6
num_tags 7
title USA Flood Hazard Areas
url https://gis-calema.opendata.arcgis.com/datasets/527151eb840d46f3aa5dcfa5ac13d561_0