This site provides free access to Iowa geographic map data, including aerial photography, orthophotos, elevation maps, and historical maps. The data is available through an on-line map viewer and through Web Map Service (WMS) connections for GIS. The site was developed by the Iowa State University Geographic Information Systems Support and Research Facility in cooperation with the Iowa Department of Natural Resources, the USDA Natural Resources Conservation Service, and the Massachusetts Institute of Technology. This site was first launched in March 1999.

Existing ROW layer was created by contacting county assessor's offices and based off of parcel data received from them. Each county has different levels of accuracy. If a county did not have a GIS parcel dataset, ERMS was utilized. Strip maps were pulled from ERMS, georectified, and traced over to created the boundary.

State_of_Iowa.zip - This is a GIS layer for the border of the state of Iowa

The Digital Surficial Geologic-GIS Map of the Iowa City East Quadrangle, Iowa is composed of GIS data layers and GIS tables, and is available in the following GRI-supported GIS data formats: 1.) an ESRI file geodatabase (icea_surficial_geology.gdb), and a 2.) Open Geospatial Consortium (OGC) geopackage. The file geodatabase format is supported with a 1.) ArcGIS Pro 3.X map file (.mapx) file (icea_surficial_geology.mapx) and individual Pro 3.X layer (.lyrx) files (for each GIS data layer). Upon request, the GIS data is also available in ESRI shapefile format. Contact Stephanie O'Meara (see contact information below) to acquire the GIS data in these GIS data formats. In addition to the GIS data and supporting GIS files, three additional files comprise a GRI digital geologic-GIS dataset or map: 1.) a readme file (heho_geology_gis_readme.pdf), 2.) the GRI ancillary map information document (.pdf) file (heho_geology.pdf) which contains geologic unit descriptions, as well as other ancillary map information and graphics from the source map(s) used by the GRI in the production of the GRI digital geologic-GIS data for the park, and 3.) a user-friendly FAQ PDF version of the metadata (icea_surficial_geology_metadata_faq.pdf). Please read the heho_geology_gis_readme.pdf for information pertaining to the proper extraction of the GIS data and other map files. QGIS software is available for free at: https://www.qgis.org/en/site/. The data were completed as a component of the Geologic Resources Inventory (GRI) program, a National Park Service (NPS) Inventory and Monitoring (I&M) Division funded program that is administered by the NPS Geologic Resources Division (GRD). For a complete listing of GRI products visit the GRI publications webpage: https://www.nps.gov/subjects/geology/geologic-resources-inventory-products.htm. For more information about the Geologic Resources Inventory Program visit the GRI webpage: https://www.nps.gov/subjects/geology/gri.htm. At the bottom of that webpage is a "Contact Us" link if you need additional information. You may also directly contact the program coordinator, Jason Kenworthy (jason_kenworthy@nps.gov). Source geologic maps and data used to complete this GRI digital dataset were provided by the following: Iowa Geological Survey. Detailed information concerning the sources used and their contribution the GRI product are listed in the Source Citation section(s) of this metadata record (icea_surficial_geology_metadata.txt or icea_surficial_geology_metadata_faq.pdf). Users of this data are cautioned about the locational accuracy of features within this dataset. Based on the source map scale of 1:100,000 and United States National Map Accuracy Standards features are within (horizontally) 50.8 meters or 166.7 feet of their actual location as presented by this dataset. Users of this data should thus not assume the location of features is exactly where they are portrayed in ArcGIS Pro, QGIS or other software used to display this dataset. All GIS and ancillary tables were produced as per the NPS GRI Geology-GIS Geodatabase Data Model v. 2.3. (available at: https://www.nps.gov/articles/gri-geodatabase-model.htm).

Clear Creek Data:

• Clear Creek DEM Hillshade Near IR U West - Near Infra-red (NIR) Lidar. Hillshade including canopy of western block in the watershed. QA/QC: By NCALM.

• Clear Creek DEM Hillshade Near IR U East - Near Infra-red (NIR) Lidar. Hillshade including canopy of eastern block in the watershed. QA/QC: By NCALM.

• Clear Creek DEM Hillshade Near IR F West - Near Infra-red (NIR) Lidar. Hillshade of topograpy without canopy of western block in the watershed. QA/QC: By NCALM.

• Clear Creek DEM Hillshade Near IR F East - Near Infra-red (NIR) Lidar. Hillshade of topograpy without canopy of eastern block in the watershed. QA/QC: By NCALM.

• Clear Creek DEM Hillshade Green Lidar F West - Green Lidar. Hillshade of topograpy without canopy of western block in the watershed. QA/QC: By NCALM.

• Clear Creek DEM Hillshade Green Lidar F East - Green Lidar. Hillshade of topograpy without canopy of eastern block in the watershed. QA/QC: By NCALM.

• Clear Creek DEM Near IR Lidar U West - Near Infra-red (NIR) Lidar. DEM including canopy of western block in the watershed. QA/QC: By NCALM.

• Clear Creek DEM Near IR Lidar U East - Near Infra-red (NIR) Lidar. DEM including canopy of eastern block in the watershed. QA/QC: By NCALM.

• Clear Creek DEM Near IR Lidar F West - Near Infra-red (NIR) Lidar. DEM of topography without canopy of western block in the watershed. QA/QC: By NCALM.

• Clear Creek DEM Near IR Lidar F East - Near Infra-red (NIR) Lidar. DEM of topography without canopy of eastern block in the watershed. QA/QC: By NCALM.

• Clear Creek DEM Green Lidar F West - Green Lidar. DEM of topography without canopy of western block in the watershed. QA/QC: By NCALM.

• Clear Creek DEM Green Lidar F East - Green Lidar. DEM of topography without canopy of eastern block in the watershed. QA/QC: By NCALM.

• Clear Creek CSD AQ 2015 - CZO Clear Creek IA - Waveform CSD Digitizer Data - CSD AQ 2015 Data.

• Clear Creek CSD AQ 2014 - Green Lidar. Raw Full Waveform Lidar. QA/QC: None.

• Clear Creek CSD NIR 2015 - CZO Clear Creek IA - Waveform CSD Digitizer Data - NIR 2015 Data.

• Clear Creek CSD NIR 2014 - Near Infra-red (NIR) Lidar. Raw Full Waveform Lidar. QA/QC: None.

• Clear Creek NIR - Near Infra-red (NIR) Lidar. Point Cloud data. QA/QC: By NCALM.

• Clear Creek AQ_532 - Green Lidar. Point Cloud data. QA/QC: By NCALM.

  GIS data in CCW - This dataset contains: * wss_gsmsoil_IA_[2006-07-06].zip = Soil data from SURRGO of the IA state * wss_SSA_IA095_soildb_IA_2003_[2016-09-22].zip = Soil data from SURRGO of watershed IA095. covers another half of CCW *. wss_SSA_IA103_soildb_IA_2003_[2016-09-22].zip = Soil data from SURRGO of watershed IA095. covers half of CCW * CCW_crop_cover_tif.zip = CCW crop cover in 2007 * ClearCreek_Streams.zip = Stream file for Clear Creek watershed in Iowa *. State_of_Iowa.zip = Shape file of the boundary of * ClearCreek_Border.zip = Shape file of the boundary of Iowa State QA/QC: Yes. * CCW 10 DEM - This dataset contains: * n42w093.zip = 10 meter resolution DEM at 42N 93W * n42w092.zip = 10 meter resolution DEM at 42N 92W * n42w091.zip = 10 meter resolution DEM at 42N 91W QA/QC: Yes. * CCW 1m lidar DEM - 1 meter resolution DEM for Clear Creek watershed QA/QC: Yes. * 2m Lidar DEM - 2 meter resolution DEM for Clear Creek watershed QA/QC: Yes.

The Digital Bedrock Geologic-GIS Map of the North, South, and Heritage Addition Units and Vicinity, Effigy Mounds National Monument, Iowa is composed of GIS data layers and GIS tables, and is available in the following GRI-supported GIS data formats: 1.) a 10.1 file geodatabase (efmo_bedrock_geology.gdb), a 2.) Open Geospatial Consortium (OGC) geopackage, and 3.) 2.2 KMZ/KML file for use in Google Earth, however, this format version of the map is limited in data layers presented and in access to GRI ancillary table information. The file geodatabase format is supported with a 1.) ArcGIS Pro map file (.mapx) file (efmo_bedrock_geology.mapx) and individual Pro layer (.lyrx) files (for each GIS data layer), as well as with a 2.) 10.1 ArcMap (.mxd) map document (efmo_bedrock_geology.mxd) and individual 10.1 layer (.lyr) files (for each GIS data layer). The OGC geopackage is supported with a QGIS project (.qgz) file. Upon request, the GIS data is also available in ESRI 10.1 shapefile format. Contact Stephanie O'Meara (see contact information below) to acquire the GIS data in these GIS data formats. In addition to the GIS data and supporting GIS files, three additional files comprise a GRI digital geologic-GIS dataset or map: 1.) a readme file (efmo_geology_gis_readme.pdf), 2.) the GRI ancillary map information document (.pdf) file (efmo_bedrock_geology.pdf) which contains geologic unit descriptions, as well as other ancillary map information and graphics from the source map(s) used by the GRI in the production of the GRI digital geologic-GIS data for the park, and 3.) a user-friendly FAQ PDF version of the metadata (efmo_bedrock_geology_metadata_faq.pdf). Please read the efmo_geology_gis_readme.pdf for information pertaining to the proper extraction of the GIS data and other map files. Google Earth software is available for free at: https://www.google.com/earth/versions/. QGIS software is available for free at: https://www.qgis.org/en/site/. Users are encouraged to only use the Google Earth data for basic visualization, and to use the GIS data for any type of data analysis or investigation. The data were completed as a component of the Geologic Resources Inventory (GRI) program, a National Park Service (NPS) Inventory and Monitoring (I&M) Division funded program that is administered by the NPS Geologic Resources Division (GRD). For a complete listing of GRI products visit the GRI publications webpage: https://www.nps.gov/subjects/geology/geologic-resources-inventory-products.htm. For more information about the Geologic Resources Inventory Program visit the GRI webpage: https://www.nps.gov/subjects/geology/gri.htm. At the bottom of that webpage is a "Contact Us" link if you need additional information. You may also directly contact the program coordinator, Jason Kenworthy (jason_kenworthy@nps.gov). Source geologic maps and data used to complete this GRI digital dataset were provided by the following: Iowa Geological Survey. Detailed information concerning the sources used and their contribution the GRI product are listed in the Source Citation section(s) of this metadata record (efmo_bedrock_geology_metadata.txt or efmo_bedrock_geology_metadata_faq.pdf). Users of this data are cautioned about the locational accuracy of features within this dataset. Based on the source map scale of 1:50,000 and United States National Map Accuracy Standards features are within (horizontally) 25.4 meters or 83.3 feet of their actual _location as presented by this dataset. Users of this data should thus not assume the _location of features is exactly where they are portrayed in Google Earth, ArcGIS, QGIS or other software used to display this dataset. All GIS and ancillary tables were produced as per the NPS GRI Geology-GIS Geodatabase Data Model v. 2.3. (available at: https://www.nps.gov/articles/gri-geodatabase-model.htm).

Linn County, Iowa census information available for download in shapefile format. Features are from 2010 census.Layers include: Blocks Block Groups TractsUpdate FrequencyAs neededAdditional ResourcesVisit Linn County, Iowa on the web.Visit Linn County, Iowa GIS on the web.Visit the Linn County, Iowa GIS portal. This site is updated as needed to reflect maps, apps, and data of interest from various County departments.Contact InformationQuestions? Contact the GIS Division by phone at 319.892.5250 or by email.

This vector tile basemap was created for use by the Iowa DOT with layers maintained by the Cartography team within Systems Planning. This basemap is a general reference set of data that includes information about transportation features (roads, railroads, airports and structures), as well as boundary information (state, county, and municipal boundaries), and surface water features (stream and lake information). The transportation features represent both the primary system as well as the local systems and rail features. The boundaries represent political jurisdictions as well as selected public interest lands. Surface waters include stream and lake locations. Given the nature of the basemap, the sources for this data are derived from many different sources, mainly from authoritative sources from within the Department of Transportation but also from authoritative sources from without. The basemap is scheduled to be updated on a quarterly cycle and the older versions will be archived.

The Digital Bedrock Geologic-GIS Map of Herbert Hoover National Historic Site and Vicinity, Iowa is composed of GIS data layers and GIS tables, and is available in the following GRI-supported GIS data formats: 1.) an ESRI file geodatabase (heho_bedrock_geology.gdb), a 2.) Open Geospatial Consortium (OGC) geopackage, and 3.) 2.2 KMZ/KML file for use in Google Earth, however, this format version of the map is limited in data layers presented and in access to GRI ancillary table information. The file geodatabase format is supported with a 1.) ArcGIS Pro 3.X map file (.mapx) file (heho_bedrock_geology.mapx) and individual Pro 3.X layer (.lyrx) files (for each GIS data layer). The OGC geopackage is supported with a QGIS project (.qgz) file. Upon request, the GIS data is also available in ESRI shapefile format. Contact Stephanie O'Meara (see contact information below) to acquire the GIS data in these GIS data formats. In addition to the GIS data and supporting GIS files, three additional files comprise a GRI digital geologic-GIS dataset or map: 1.) a readme file (heho_geology_gis_readme.pdf), 2.) the GRI ancillary map information document (.pdf) file (heho_geology.pdf) which contains geologic unit descriptions, as well as other ancillary map information and graphics from the source map(s) used by the GRI in the production of the GRI digital geologic-GIS data for the park, and 3.) a user-friendly FAQ PDF version of the metadata (heho_bedrock_geology_metadata_faq.pdf). Please read the heho_geology_gis_readme.pdf for information pertaining to the proper extraction of the GIS data and other map files. Google Earth software is available for free at: https://www.google.com/earth/versions/. QGIS software is available for free at: https://www.qgis.org/en/site/. Users are encouraged to only use the Google Earth data for basic visualization, and to use the GIS data for any type of data analysis or investigation. The data were completed as a component of the Geologic Resources Inventory (GRI) program, a National Park Service (NPS) Inventory and Monitoring (I&M) Division funded program that is administered by the NPS Geologic Resources Division (GRD). For a complete listing of GRI products visit the GRI publications webpage: https://www.nps.gov/subjects/geology/geologic-resources-inventory-products.htm. For more information about the Geologic Resources Inventory Program visit the GRI webpage: https://www.nps.gov/subjects/geology/gri.htm. At the bottom of that webpage is a "Contact Us" link if you need additional information. You may also directly contact the program coordinator, Jason Kenworthy (jason_kenworthy@nps.gov). Source geologic maps and data used to complete this GRI digital dataset were provided by the following: Iowa Geological and Water Survey and Iowa Geological Survey. Detailed information concerning the sources used and their contribution the GRI product are listed in the Source Citation section(s) of this metadata record (heho_bedrock_geology_metadata.txt or heho_bedrock_geology_metadata_faq.pdf). Users of this data are cautioned about the locational accuracy of features within this dataset. Based on the source map scale of 1:500,000 and United States National Map Accuracy Standards features are within (horizontally) 254 meters or 833.3 feet of their actual location as presented by this dataset. Users of this data should thus not assume the location of features is exactly where they are portrayed in Google Earth, ArcGIS Pro, QGIS or other software used to display this dataset. All GIS and ancillary tables were produced as per the NPS GRI Geology-GIS Geodatabase Data Model v. 2.3. (available at: https://www.nps.gov/articles/gri-geodatabase-model.htm).

This site provides free access to Iowa geographic map data, including aerial photography, orthophotos, elevation maps, and historical maps. The data is available through an on-line map viewer and through Web Map Service (WMS) connections for GIS. The site was developed by the Iowa State University Geographic Information Systems Support and Research Facility in cooperation with the Iowa Department of Natural Resources, the USDA Natural Resources Conservation Service, and the Massachusetts Institute of Technology. This site was first launched in March 1999.

The Digital Surficial Geologic-GIS Map of Herbert Hoover National Historic Site and Vicinity, Iowa is composed of GIS data layers and GIS tables, and is available in the following GRI-supported GIS data formats: 1.) an ESRI file geodatabase (heho_surficial_geology.gdb), a 2.) Open Geospatial Consortium (OGC) geopackage, and 3.) 2.2 KMZ/KML file for use in Google Earth, however, this format version of the map is limited in data layers presented and in access to GRI ancillary table information. The file geodatabase format is supported with a 1.) ArcGIS Pro 3.X map file (.mapx) file (heho_surficial_geology.mapx) and individual Pro 3.X layer (.lyrx) files (for each GIS data layer). The OGC geopackage is supported with a QGIS project (.qgz) file. Upon request, the GIS data is also available in ESRI shapefile format. Contact Stephanie O'Meara (see contact information below) to acquire the GIS data in these GIS data formats. In addition to the GIS data and supporting GIS files, three additional files comprise a GRI digital geologic-GIS dataset or map: 1.) a readme file (heho_geology_gis_readme.pdf), 2.) the GRI ancillary map information document (.pdf) file (heho_geology.pdf) which contains geologic unit descriptions, as well as other ancillary map information and graphics from the source map(s) used by the GRI in the production of the GRI digital geologic-GIS data for the park, and 3.) a user-friendly FAQ PDF version of the metadata (heho_surficial_geology_metadata_faq.pdf). Please read the heho_geology_gis_readme.pdf for information pertaining to the proper extraction of the GIS data and other map files. Google Earth software is available for free at: https://www.google.com/earth/versions/. QGIS software is available for free at: https://www.qgis.org/en/site/. Users are encouraged to only use the Google Earth data for basic visualization, and to use the GIS data for any type of data analysis or investigation. The data were completed as a component of the Geologic Resources Inventory (GRI) program, a National Park Service (NPS) Inventory and Monitoring (I&M) Division funded program that is administered by the NPS Geologic Resources Division (GRD). For a complete listing of GRI products visit the GRI publications webpage: https://www.nps.gov/subjects/geology/geologic-resources-inventory-products.htm. For more information about the Geologic Resources Inventory Program visit the GRI webpage: https://www.nps.gov/subjects/geology/gri.htm. At the bottom of that webpage is a "Contact Us" link if you need additional information. You may also directly contact the program coordinator, Jason Kenworthy (jason_kenworthy@nps.gov). Source geologic maps and data used to complete this GRI digital dataset were provided by the following: Iowa Geological Survey. Detailed information concerning the sources used and their contribution the GRI product are listed in the Source Citation section(s) of this metadata record (heho_surficial_geology_metadata.txt or heho_surficial_geology_metadata_faq.pdf). Users of this data are cautioned about the locational accuracy of features within this dataset. Based on the source map scale of 1:100,000 and United States National Map Accuracy Standards features are within (horizontally) 50.8 meters or 166.7 feet of their actual location as presented by this dataset. Users of this data should thus not assume the location of features is exactly where they are portrayed in Google Earth, ArcGIS Pro, QGIS or other software used to display this dataset. All GIS and ancillary tables were produced as per the NPS GRI Geology-GIS Geodatabase Data Model v. 2.3. (available at: https://www.nps.gov/articles/gri-geodatabase-model.htm).

This feature layer contains Linn County, Iowa parcel geometry joined to County tax system information. Parcel geometry is maintained by the Real Estate Division within the Auditor's Office. Update FrequencyApproximately daily Additional ResourcesVisit Linn County, Iowa on the web. Visit Linn County, Iowa GIS on the web. This site is updated as needed to reflect maps, apps, and data of interest from various County departments. Contact InformationQuestions? Contact the GIS Division by phone at 319.892.5250 or by email.

This web mapping service is intended to provide information on Iowa's wetlands. In particular, data recorded in the National Wetland Inventory.

Land cover in the USand the CCW - The land cover data is collected annually from USDA for the whole US. The data can be downloaded here https://nassgeodata.gmu.edu/CropScape/. Data resolution is 30 *30 m. The available data period for both USRB and CCW is from 2008 till 2015

This coverage contains the section lines for the Public Land Survey System (PLSS). These lines form polygons which are labelled for PLSS township, range and section number. Coordinates were digitized from U. S. Geological Survey 7.5' topographic maps (paper copies) using a digitizing program developed in-house by the Geological Survey Bureau, Iowa DNR. The digitizing tablet accuracy was 1/50 inch. Section lines from individual quads were combined and edited using PC Arc/Info.

The TIGER/Line shapefiles and related database files (.dbf) are an extract of selected geographic and cartographic information from the U.S. Census Bureau's Master Address File / Topologically Integrated Geographic Encoding and Referencing (MAF/TIGER) Database (MTDB). The MTDB represents a seamless national file with no overlaps or gaps between parts, however, each TIGER/Line shapefile is designed to stand alone as an independent data set, or they can be combined to cover the entire nation. The TIGER/Line shapefiles include both incorporated places (legal entities) and census designated places or CDPs (statistical entities). An incorporated place is established to provide governmental functions for a concentration of people as opposed to a minor civil division (MCD), which generally is created to provide services or administer an area without regard, necessarily, to population. Places always nest within a state, but may extend across county and county subdivision boundaries. An incorporated place usually is a city, town, village, or borough, but can have other legal descriptions. CDPs are delineated for the decennial census as the statistical counterparts of incorporated places. CDPs are delineated to provide data for settled concentrations of population that are identifiable by name, but are not legally incorporated under the laws of the state in which they are located. The boundaries for CDPs often are defined in partnership with state, local, and/or tribal officials and usually coincide with visible features or the boundary of an adjacent incorporated place or another legal entity. CDP boundaries often change from one decennial census to the next with changes in the settlement pattern and development; a CDP with the same name as in an earlier census does not necessarily have the same boundary. The only population/housing size requirement for CDPs is that they must contain some housing and population. The boundaries of most incorporated places in this shapefile are as of January 1, 2021, as reported through the Census Bureau's Boundary and Annexation Survey (BAS). The boundaries of all CDPs were delineated as part of the Census Bureau's Participant Statistical Areas Program (PSAP) for the 2020 Census.

Welcome to the Iowa Department of Transportation DOT Portal. The Viewer allows you to display and interact with online maps. This means that you can annotate and save a particular map, share a map with others, search for data, zoom or pan to specific features, and run and print reports.

The TIGER/Line shapefiles and related database files (.dbf) are an extract of selected geographic and cartographic information from the U.S. Census Bureau's Master Address File / Topologically Integrated Geographic Encoding and Referencing (MAF/TIGER) Database (MTDB). The MTDB represents a seamless national file with no overlaps or gaps between parts, however, each TIGER/Line shapefile is designed to stand alone as an independent data set, or they can be combined to cover the entire nation.Census Blocks are statistical areas bounded on all sides by visible features, such as streets, roads, streams, and railroad tracks, and/or by nonvisible boundaries such as city, town, township, and county limits, and short line-of-sight extensions of streets and roads. Census blocks are relatively small in area; for example, a block in a city bounded by streets. However, census blocks in remote areas are often large and irregular and may even be many square miles in area. A common misunderstanding is that data users think census blocks are used geographically to build all other census geographic areas, rather all other census geographic areas are updated and then used as the primary constraints, along with roads and water features, to delineate the tabulation blocks. As a result, all 2020 Census blocks nest within every other 2020 Census geographic area, so that Census Bureau statistical data can be tabulated at the block level and aggregated up to the appropriate geographic areas. Census blocks cover all territory in the United States, Puerto Rico, and the Island Areas (American Samoa, Guam, the Commonwealth of the Northern Mariana Islands, and the U.S. Virgin Islands). Blocks are the smallest geographic areas for which the Census Bureau publishes data from the decennial census. A block may consist of one or more faces.The TIGER/Line shapefiles and related database files (.dbf) are an extract of selected geographic and cartographic information from the U.S. Census Bureau's Master Address File / Topologically Integrated Geographic Encoding and Referencing (MAF/TIGER) Database (MTDB). The MTDB represents a seamless national file with no overlaps or gaps between parts, however, each TIGER/Line shapefile is designed to stand alone as an independent data set, or they can be combined to cover the entire nation.

The Watershed Boundary Dataset (WBD) defines the areal extent of surface water drainage to a point, accounting for all land and surface areas. Watershed Boundaries are determined solely upon science-based hydrologic principles, not favoring any administrative boundaries or special projects, nor particular program or agency. The intent of defining Hydrologic Units (HU) for the Watershed Boundary Dataset is to establish a base-line drainage boundary framework, accounting for all land and surface areas. At a minimum, the WBD is being delineated and georeferenced to the USGS 1:24,000 scale topographic base map meeting National Map Accuracy Standards (NMAS). Hydrologic units are given a Hydrologic Unit Code (HUC). For example, a hydrologic region has a 2-digit HUC. A HUC describes where the unit is in the country and the level of the unit."A hydrologic unit is a drainage area delineated to nest in a multi-level, hierarchical drainage system. Its boundaries are defined by hydrographic and topographic criteria that delineate an area of land upstream from a specific point on a river, stream or similar surface waters. A hydrologic unit can accept surface water directly from upstream drainage areas, and indirectly from associated surface areas such as remnant, non-contributing, and diversions to form a drainage area with single or multiple outlet points. Hydrologic units are only synonymous with classic watersheds when their boundaries include all the source area contributing surface water to a single defined outlet point."

A map showing the Farm to Market routes in Iowa.