January 2023 - Census population data were downloaded for 2020 and appended to the county dataset. Population fields were re-ordered and named for consistency.April 2013 - Census data were downloaded for 2010 and appended to the county coverage. Upon further review by the ND GIS Technical Meeting at their April 2013 meeting, it was decided that the demographic data included with the previous county feature class would be dropped, leaving only basic information with the necessary relational fields intact for joining of Census data tables and other related North Dakota data.The North Dakota county coverage was originally created by the North Dakota Geological Survey using US Census Bureau TIGER data in 1994. The source scale on these data was 1:100,000. Since its creation, with USGS Public Land Survey DLG data, and USGS DRG derived data. The North Dakota State Water Commission revamped this coverage by using the NDGS PLSS coverage (combination of ND PSC, USGS DLG and DRG 24k data) to obtain county boundaries that coincided with PLSS linework, and heads-up digitized irregular boundaries such as that on the State borders, and those that followed river/stream boundaries with USGS 1:24,000 scale Digital Raster Graphics. The resultant coverage should be much better than a 1:100,000 scale coverage, but may not meet 1:24,000 scale accuracy standards.

These maps can be used to determine what a county has for GIS data, if they charge for it, and who the primary GIS contact(s) is/are. These maps are presented as a general guide and are not the definitive source for all county information.

Constraints:
Not to be used for navigation, for informational purposes only. See full disclaimer for more information

Representation of tax parcel boundaries with associated attributes in Cass County, ND.

Geometry may be duplicated where one-to-many relationships exist, such as condominium units. Mobile homes are represented by 6-digit parcel identification numbers.For more information contact Cass County GIS.For tax parcel information contact the Tax Equalization office.

This coverage contains information about the buried valleys within the Standing Rock Indian Reservation, Sioux County, North Dakota, and Corson County, South Dakota. The delineation of the buried valleys was included as part of the surficial geology map (figure 5) created by Howells (1982). The digital data were produced by the U.S. Geological Survey (USGS) in cooperation with the U.S. Environmental Protection Agency. Figure 5 in Howells (1982) was scanned and digitized on-screen to create this coverage. See cross reference information for more detail. According to the map credit for figure 5, the geology for Sioux County was based on soil maps prepared by the U.S. Bureau of Indian Affairs (1959), data collected by Randich (1975), and a geologic map by Carlson (1978). The geology for Corson County was based on soil maps prepared by the U.S. Bureau of Indian Affairs (1959) and unpublished maps of the U.S Soil Conservation Service, modified by test drilling and field reconnaissance.

8/04/2025 - Updates to Mandan and Thompson. 4/25/2025 - Updates to Ellendale, Fargo, Kindred, Lincoln, Mandan, Rugby and Tappen.12/06/2024 - Update to Lincoln and Bismarck Corporate Boundaries based on requests from Lincoln.6/27/2024 - Update to the Valley City and Dickinson Corporate Boundary based on requests from their GIS personal.4/8/2024 - Update to the Valley City Corporate Boundary12/04/2023 - Update to Fargo City Boundary7/23/2023 - Removed Church’s Ferry due to proclamation and notice of dissolution.7/01/2023 - Changes to Binford - Ordinance 51; Lidgerwood - Ordinance 2022-1; Killdeer Golf Course annexation; Bismarck based on current City of Bismarck GIS boundary9/26/2022 - Changes to Steele boundary per Kidder County 911 coordinator.9/23/2022 - Updates to Grand Forks, Mandan and Fargo7/01/2022 - Updates to Killdeer, Mandan and Williston per State Tax Dept changes. 2/14/2022- Updates to Minot -13th ST SE/31st AVE SE, Updates to Elgin, Horace and St. John.11/16/2021 -Updates to Bismarck, Fargo and Killdeer based on city ordinances.7/2/21 – Changes were made to the City of Bismarck, Fargo and Hillsboro to include local taxing jurisdiction boundary changes from the State Tax Commissioner.5/4/21 - Updates were made to the City of Wahpeton due to an annexation.4/29/21 - Updated Minot and Makoti3/5/21 - Updated an annexation to Arnegard that was submitted to the DOT by Mackenzie's County Public Works GIS Coordinator.1/21/21 - Update to Sentinel Butte per Golden Valley 911 Coordinator7/17/20 - Updates to Bismarck, Linton and Stanley6/1/20 - Updates to Killdeer, New Town and Surrey1/17/2020 - Boundary changes have been updated for Bismarck, Bowman Fargo, Garrison, Linton, and New Salem.3/5/19 - The corporate boundary of Surrey has been updated.12/26/18 - The following corporate boundaries have been updated: Bismarck, Lincoln, Grand Forks, Horace, Casselton, Fargo, Oxbow, Tioga and Stanley.6/19/18 - City of Maza is not incorporated based on the 2011-2013 North Dakota Blue book. Removed Maza.5/14/18 - Updated Dickinson, Watford City, Berthold, Minnewauken, and Cavalier.1/31/18 - Updated Dickinson, Mandan, Minot, Tioga, Devils Lake, Belfield, Washburn, Mohall, Minnewauken, Lincoln, Bismarck and Casselton. 10/24/17 - Updated Watford City and Makoti10/16/17 - The following cities have been updated: Jamestown, Milnor, Bismarck, Carrington, Casselton, Mandan, Minot, Stanley, Larimore, Crosby, and Watford City.1/10/17 - The following cities have been updated: Lehr, Grand Forks, Langdon, Drayton, Flasher, Glen Ullin, Watford City, Zap, Lignite, Hankinson, Beach, Underwood, South Heart, Devils Lake, all cities in Ward County, Cavalier, Bismarck, Lincoln, Fargo, West Fargo, Ayr, Briarwood, Casselton, Davenport, Enderlin, Grandin, Horace, and North River.9/19/16 - Updated the following cities: Watford City, Steele, Richardton, Berthold, Carpio, Burlington, Des Lacs, Donnybrook, Douglas, Kenmare, Makoti, Ryder, Sawyer, and Surrey.6/23/16 - Updated cities are as follows: All cities in Pembina, Morton, Richland, and Williams Counties. The cities of Bismarck, West Fargo, Harwood, Oxbow, Beach, Minot, Stanley, Jamestown, Fargo, Dickinson and New Town.9/28/15 - The following cites have had annexation: Stanley, Bottineau, Minot, Casselton, Belfield and Watford City.7/24/15 - Updated Grafton, Stanley, Bismarck, Williston, Horace, Fargo, Grand Forks, Watford City, Turtle Lake, Leeds, Maxbass and Medora1/16/15 - Updated Grafton, Stanley and Bismarck.11/3/2014 - Updated Bismarck, Mandan, Minot, Stanley, and Watford City7/16/14 - Corporate limits updated include: Mandan, Towner, Fargo, West Fargo, Grand Forks, Bismarck, Bowman, Watford City, Stanley, Tioga, Kenmare, Casselton, Minot, Carrington, Kindred, and Killdeer. The corporate limit updates consisted of receiving from the cities, shape files, CADD files, scanned images of annexations or by converting pdf files into images, rectifying them within ArcGIS, then heads-up digitizing. 7/29/13 - updated Stanley, Williston, Minot, and Bismarck.4/30/13 - updated Williston, Hazen, Minot, Dickinson, Valley City, Velva, Rugby, Bismarck, and Lincoln1/28/13 - updated Valley City, Grand Forks, Bismarck, Williston, Jamestown, Harvey, Mohall, Park River, Ray, Rugby, Stanley, Tioga, Mayville and Glenfield10/9/12 - updated Williston and Dickinson6/20/12 - updated Williston via shapefile from city.3/20/12 - updated Bismarck and Minot10/3/2011 - Edited corporate limits for Bottineau, Grand Forks, Bismarck, Grafton, Fargo, West Fargo, Horace, Dickinson, Williston, Valley City and Devils Lake.2/4/11 - Removed urban areas so only corporate boundaries remain. Removed boolean field named URBAN_AREA. Updated corporate limist in Dickinson and cities with Cass county. 6/24/10 - Stanley, Lincoln, Oakes, Hankinson, Enderlin, Ellendale, Linton, Carrington, Minot, and Kulm corportate limits were changed 6/18/09 - Stanley, Wahpeton, Center, Watford City, Williston, Grand Forks, Killdeer, Beulah, Beach, Hazen, Garrison, Washburn, Bismarck and Lincoln corporate limits were changed 3/24/08 - Added Milton, Drayton, and Cavalier Boudaries updated: Park River 1/16/08 - Boundaries updated: Devils Lake, Glen Ullin, Langdon, Minnewaukan, Northwood, Thompson 2/13/07 - Boundaries updated: Amenia, Arthur, Bismarck, Bottineau, Buffalo, Casstleton, Davenport, Dickinson, Enderlin, Gardner, Grand Forks, Grandin, Harvey, Harvey, Hillsboro, Horace, Hunter, Jamestown, Kindred, Mapleton, Mayville, New Rockford, Oxbox, Page, Prairie Rose, Relies Acres, Tappen, Towner City 1/10/06 - Boundaries updated: Wishek, Fargo, Lincoln, Bottineau, Williston, Grand Forks, Granville, Velva, Stanley, urban areas in Fargo, West Fargo, Bismarck and Mandan. Deleted Larson This data came from the NDDOT's Mapping Section. The original data was digitized from hand scribed maps and registered to the 1:24000 USGS PLSS data. It was converted from a projection (NAD 1983 UTM Zone 14N) to a Geographic coordinate system.

Originally produced by the Farm Security Administration, these are georeferenced aerial images from Morton County, North Dakota. Historic print images housed at the Mandan, North Dakota ARS Long-Term Agricultural Research facility were digitized, georeferenced, and processed for use in both professional and consumer level GIS applications, or in photo-editing applications. The original images were produced by the Farm Security Administration to monitor government compliance for farm land agreements. Current applications include assessing land use change over time with regard to erosion, land cover, and natural and man-made structures. Not for use in high precision applications. Resources in this dataset:Resource Title: 1938_AZY_3_89. File Name: 1938_AZY_3_89_0.zipResource Description: Contains IIQ, JPG, OVR, XML, AUX, and TIF files processed in ArcMap / ArcGIS that can be used in ArcGIS applications, or in other photo or geospatial applications. Resource Title: 1938 Mosaic Index. File Name: 1938_mosaic_index_1.zipResource Description: This is the index key for the 1938 Mandan aerial images from Morton County, ND. To find the geographic location for each uploaded 1938 image, consult this map. File titles are arranged as follows: Year_Area_Roll_Frame. The mosaic map displays Roll_Frame coordinates to correspond to these images. Contains TIF, OVR, JPG, AUX, IIQ, and XML files. Resource Title: 1938_AZY_5_113. File Name: 1938_AZY_5_113_2.zipResource Description: Contains IIQ, JPG, OVR, XML, AUX, and TIF files processed in ArcMap / ArcGIS.

The Statewide Parcel Project was funded by the 66th Legislative Assembly, appropriating funds through House Bill 1021. During the 2019-2021 Biennium, AppGeo aggregated parcel boundary and tax roll data from 51 counties and developed parcel boundary data for Adams and Benson counties.Beginning in the 2021-2023 Biennium the parcel dataset will be maintained on a regular basis using funding provided by the 67th Legislative Assembly and leveraging the existing North Dakota GIS Hub infrastructure. Data maintenance will consist of parcel boundary and tax roll data being submitted by counties and their vendors and/or harvested by the GIS Hub. The frequency of data updates will vary by county, ranging from monthly to yearly. To obtain the most recent data for a county, that county should be contacted.IMPORTANT: If you wish to download this entire dataset rather than stream the data as a web service, we suggest you use the 'Download Zipped fGDB' link. The other download options may take several minutes to generate.IMPORTANT: Please see the metadata for Limitations of UseOTHER NOTES:Rural parcels are the focus of the Statewide Parcel Program. In the future, city parcels may be filled in where currently missing.There is a one-to-many relationship between the parcels feature class and the tax roll table, based on the UniqueGISID attribute in each dataset.What appears to be missing parcel boundaries may be due to things such as:State and federal lands - refer to the GIS Hub Portal for these datasetsCities - some cities are included in the data submitted by the counties and their vendors, some are notInvalid geometry - issues with the data are flagged and stored in the 'Invalid Geometry' feature class

This image service contains high-resolution land cover data for the states of Nebraska, South Dakota, and North Dakota. These data are a digital representation of land cover derived from 1-meter aerial imagery from the USDA National Agriculture Imagery Program (NAIP.) The year of NAIP used for each state was 2014.Data are intended for use in rural areas and therefore do not include land cover in cities and towns. Land cover classes (tree cover, other land cover, or water) were mapped using an object-based image analysis approach and supervised classification. These data are designed for conducting geospatial analyses and for producing cartographic products. In particular, these data are intended to depict the location of tree cover in the county. The mapping procedures were developed specifically for agricultural landscapes that are dominated by annual crops, rangeland, and pasture and where tree cover is often found in narrow configurations, such as windbreaks and riparian corridors. Because much of the tree cover in agricultural areas of the United States occurs in windbreaks and narrow riparian corridors, many geospatial datasets derived from coarser-resolution satellite data (such as Landsat), do not capture these landscape features. This dataset is intended to address this particular data gap. These data can be downloaded by county at the Forest Service Research Data Archive. Nebraska: https://www.fs.usda.gov/rds/archive/catalog/RDS-2019-0038 South Dakota: https://www.fs.usda.gov/rds/archive/catalog/RDS-2022-0068 North Dakota: https://www.fs.usda.gov/rds/archive/catalog/RDS-2022-0067 A Kansas dataset was also developed using the same methods and is located at: Kansas data download: https://www.fs.usda.gov/rds/archive/catalog/RDS-2019-0052 Kansas map service: https://data-usfs.hub.arcgis.com/documents/high-resolution-tree-cover-of-kansas-2015-map-service/explore

11/22/2024 - Addition of part of former Oberon Fire Dept to Minnewaukan Rural. Addition of part of former Oberon Fire Dept into Maddock Rural Fire Dept. Changes to Bismarck City and Bismarck Rural Fire Dept based on Cooperate Boundary Changes. Addition to Great Carson Fire Dept. Removal of following fire dept that have been dissolved – Edna Rural, Oriska, Emerado and Solan F/P.6/27/2024 - Update to the Valley City and Dickinson Corporate Boundary based on requests from their GIS personal.4/8/2024 - Update to the Valley City Corporate Boundary.12/04/2023 - Updates to Marion Combines, Oberon Dissolution, City of Fargo boundary changes, Bowdon/Goodrich Boundary, Rutland Cayauga/Forman boundary11/08/2023 - Harwood Fire Department Boundary was verified.07/01/2023 - Bismarck Corporate Boundary based on current City of Bismarck GIS boundary10/1/2022 - Addition of Westby Fire Department, Updates to Mandan Fire Protection District and Mandan City Fire based on Mandan Corporate Boundary Change, Update to Bismarck Fire Protection District and Bismarck City Fire due to Bismarck Corporate Boundary Changes (June 2022), Update to Grand Forks City Fire, Ferry Township Fire Protection District and Thompson Fire Protestion District due to changes in Grand Forks Corporate Boundary. Updates to Fargo City Fire and Horace Fire Protection District due to changes in Fargo Corporate Boundary. 2/14/2022- Aligned Minot to corresponding City Boundary11/16/2021- Updated Rural/City Fire Districts to reflect changes in Corporate Boundaries in Fargo, Killdeer and Bismarck.5/4/21 - Created separate Fire District polygons for all city fire departments. Removed city fire department area from rural fire departments. Combined Pembina Fire Departments into one district – 4000. Updates to Sheyenne Rural Territory Lines. Modified Minot and Wahpeton to match corporate boundary changes.2/12/20 - 2851 - Kulm Rural Fire Department and 1561 - Ellendale Fire Protection District was changed to fix a discrepancy provided by the Dickey County Emergency Manager.1/17/20 - 0901 – Casselton Rural Fire Department has become 0900 – Casselton Fire Department. 1811 – Forman – Havana Fire Protection District has become Forman Fire Protection District. 3001 – Lehr Rural Fire Department becomes 3001 - Lehr Fire Department.10/2/18 - A new fire district was created in Dunn and Mercer counties called Twin Buttes Fire Protection District. The new Fire District number is 4911.1/24/18 - The following districts have been updated: Adams Fire Protection District, Ashley Rural Fire Department, Edgeley Rural Fire Department, Edinburg Fire Protection District, Edmore Rural Fire Department, Ellendale Fire Protection District, Fairdale Fire Protection District, Grafton Fire Protection District, Hoople Fire Protection District, Kulm Rural Fire Department, Lankin Fire Protection District, Lehr Rural Fire Department, Michigan Fire Protection District, Park River Fire Protection District, Pisek Fire Protection District, and Wishek Fire Protection District.10/3/17 by bb - From ND Insurance Dept. - the 0000 districts are for districts where there isn't a certified fire department with a fire marshall's office - there are ~10 areas that have this code.1/10/17 - The following districts were edited: Ashley Rural Fire Department, Kulm Rural Fire Department, Leeds Fire Protection District, Spirit Lake Fire Department, Minnewauken Fire Protection District, Bowbells Fire Protection District and Lignite Fire Protection District 1/16/15 - Flaxton Fire Protection District was dissolved and incorporated into the Lignite Fire Protection district and the Bowbells Fire Protection District. Oakes Fire Protection District was updated to match the map sent in by their district.1/28/13 - The following Fire Districts were changed during the 2012 calendar year: Jamestown Fire Protection District, Pingree Fire Protection District, Kenmare Rural Fire Department, Tolley Fire Department, Wales Fire Department, Langdon Fire Protection District, Hampden Fire Protection District Munich Fire Protection District and Nekoma Fire Protection District.1/23/09 Counties: Towner, Benson,Ramsey - Leeds Fire District Counties: Grand Forks - Addition of the Grand Forks Fire District. Possible omission during digital conversion??? Counties: Kidder,Dickey - Dissolved the Merricourt Fire District Counties: Pembina - Matched the map received from Pembina County. 2/25/08 Based data is being maintained in UTM Zone 14N. The data was unprojected via ArcMap for use on the Hub. The information came from Ken Rood and the Insurance Commission. For years the NDDOT would use ChartPak tape and tape the boundaries on our 11 X 17 County Base Maps. Deciding the need for a digital layer, the mapping section started to create the layer during the winter of 2006/2007. The section line layer was used to snap the Fire District Boundaries to. The layer was created in ArcMap and the names and fire district codes were given to us by the Insurance Commission. A geodatabase was created for the layer and topology rules were created to eliminate overlaps and slivers. The link to the maps on the Insurance Commissions site is http://www.nd.gov/ndins/company/details.asp?ID=321

BackgroundAlthough the burden of the coronavirus disease 2019 (COVID-19) has been different across communities in the US, little is known about the disparities in COVID-19 burden in North Dakota (ND) and yet this information is important for guiding planning and provision of health services. Therefore, the objective of this study was to identify geographic disparities of COVID-19 hospitalization risks in ND.MethodsData on COVID-19 hospitalizations from March 2020 to September 2021 were obtained from the ND Department of Health. Monthly hospitalization risks were computed and temporal changes in hospitalization risks were assessed graphically. County-level age-adjusted and spatial empirical Bayes (SEB) smoothed hospitalization risks were computed. Geographic distributions of both unsmoothed and smoothed hospitalization risks were visualized using choropleth maps. Clusters of counties with high hospitalization risks were identified using Kulldorff's circular and Tango's flexible spatial scan statistics and displayed on maps.ResultsThere was a total of 4,938 COVID-19 hospitalizations during the study period. Overall, hospitalization risks were relatively stable from January to July and spiked in the fall. The highest COVID-19 hospitalization risk was observed in November 2020 (153 hospitalizations per 100,000 persons) while the lowest was in March 2020 (4 hospitalizations per 100,000 persons). Counties in the western and central parts of the state tended to have consistently high age-adjusted hospitalization risks, while low age-adjusted hospitalization risks were observed in the east. Significant high hospitalization risk clusters were identified in the north-west and south-central parts of the state.ConclusionsThe findings confirm that geographic disparities in COVID-19 hospitalization risks exist in ND. Specific attention is required to address counties with high hospitalization risks, especially those located in the north-west and south-central parts of ND. Future studies will investigate determinants of the identified disparities in hospitalization risks.

Sheridan County, ND has a C wealth grade. Median household income: $69,343. Unemployment rate: 1.1%. Income grows 5.3% yearly.

This resource contains four map drafts of the Mississinewa Reservoir with reference to county lines, waterways, archaeological sites and other geological and topographical details. These maps are part of the Mississinewa Reservoir Maps N.D collection that consists of oversized maps of the Mississinewa Reservoir within Grant, Miami, and Wabash Counties, Indiana. The collection was received without any association to a particular investigation. The date of this image was not recorded. It is likely that this is due to the documents’ large size and cartographic contents.

This data release consists of the following components: Sex ratio data from cottonwood trees at random points on the floodplain in the North and South units of Theodore Roosevelt National Park, ND. These data were used to investigate the effects of age, height above, and distance from the channel on mortality of male and female trees of plains cottonwood (Populus deltoides subsp. monilifera) as described in the Friedman and Griffin (2017) report. Tree core and tree ring data from the North and South Units of Theodore Roosevelt National Park, North Dakota. South Unit data was collected in April 2012, North Unit data was collected in the summer and fall of 2010. The trees are located on the floodplain of the Little Missouri River in Theodore Roosevelt National Park. These data were used to reconstruct flow and climate as described in the Friedman and Griffin (2017) report and in other documents cited by that report. The tree ring data is presented in Standard Tucson format. Floodplain and riparian cottonwood forest areas in the South Unit were digitized as separate shapefiles using 2010 NAIP imagery. They were mapped to assist management of cottonwood forests by increasing understanding of the relation between geomorphic setting, flow, precipitation, temperature, and other factors. Edges of water, channel centerline, valley bottom centerline, extent of valley bottom, and estimated bankfull channel data for the Little Missouri River in the North and South Units were mapped as separate shapefiles from 2010 NAIP imagery as well.

Data were collected in August, 2020 to support development of a bathymetric map for Larimore Dam in Grand Forks County, North Dakota. Global Navigation Satellite System (GNSS) surveying equipment was used in static and real-time kinematic (RTK) mode to establish a local reference mark and check-in/check-out point, to collect water surface elevations, and to collect topographic points along established data collection transects. Topographic points were collected on land, in water too shallow for boating, and in areas of the lake where thick aquatic vegetation prohibited use of an echosounder and transducer. In areas of the lake deep enough for boating and where aquatic vegetation was not present, depth data was collected using an echosounder with a dual frequency (200/24 kilohertz with a 4/20 degree beam) transducer. Data were collected on a set of transects roughly perpendicular to the axis of the waterbody, plus on a set of oblique transects that intersected the regular transects ...

Grand Forks County, ND has a C wealth grade. Median household income: $68,149. Unemployment rate: 2.6%. Income grows 4.3% yearly.

Dunn County, ND has a B wealth grade. Median household income: $92,605. Unemployment rate: 2.6%. Income grows 4.1% yearly.

Divide County, ND has a B wealth grade. Median household income: $93,054. Unemployment rate: 3.0%. Income grows 5.8% yearly.

The North Dakota county coverage was originally created by the North Dakota Geological Survey using US Census Bureau TIGER data in 1994. The source scale on these data was 1:100,000. Since its creation, with USGS Public Land Survey DLG data, and USGS DRG derived data. The North Dakota State Water Commission revamped this coverage by using the NDGS PLSS coverage (combination of ND PSC, USGS DLG and DRG 24k data) to obtain county boundaries that coincided with PLSS linework, and heads-up digitized irregular boundaries such as that on the State borders, and those that followed river/stream boundaries with USGS 1:24,000 scale Digital Raster Graphics. The resultant coverage should be much better than a 1:100,000 scale coverage, but may not meet 1:24,000 scale accuracy standards

This coverage contains information about the western limit of glaciation within the Standing Rock Indian Reservation, Sioux County, North Dakota, and Corson County, South Dakota. The digital data were produced by the U.S. Geological Survey (USGS) in cooperation with the U.S. Environmental Protection Agency. Figure 5 in Howells (1982) was scanned and digitized on-screen to create this coverage. See cross reference information for more detail. According to the map credit for figure 5, the geology for Sioux County was based on soil maps prepared by the U.S. Bureau of Indian Affairs (1959), data collected by Randich (1975), and a geologic map by Carlson (1978). The geology for Corson County was based on soil maps prepared by the U.S. Bureau of Indian Affairs (1959) and unpublished maps of the U.S Soil Conservation Service, modified by test drilling and field reconnaissance. The following is from the description of the surficial geology by Howells (1982). The surface geology, like the topography, has been strongly influenced by continental glaciation and by Pleistocene erosion on a land surface underlain by soft unconsolidated deposits of continental and marine shale and sandstone. The Standing Rock Indian Reservation is on the western margin of the midwestern area that was invaded by great ice sheets during the last million years. Though at most only 60 percent of the reservation apparently was covered by glacial ice, the effects of the glaciers were pervasive: not only did the ice sheets grind away the land surface in the areas that they invaded, but they also changed the courses of rivers and created a new river--the Missouri. In addition, changes in weather patterns associated with glaciation profoundly influenced streamflow and erosion in the area not reached by the ice sheets. Because the Standing Rock Indian Reservation was on the border of the glaciated region, much of the area is free of glacial deposits and most of the glacial deposits present are thin, discontinuous, and of negligible hydrologic importance.

This coverage contains information about the surficial geology for the area within the Standing Rock Indian Reservation, Sioux County, North Dakota, and Corson County, South Dakota. Identified units include: 1) alluvium, terrace, outwash, colluvium, eolian deposits, and buried-valley fill; 2) glacial till; 3) Fort Union Formation; 4) Hell Creek Formation; 5) Fox Hills Formation; and 6) Pierre Shale. The digital data were produced by the U.S. Geological Survey (USGS) in cooperation with the U.S. Environmental Protection Agency.

Figure 5 in Howells (1982) was scanned and digitized on-screen to create this coverage. See cross reference information for more detail.

According to the map credit for figure 5, the geology for Sioux County was based on soil maps prepared by the U.S. Bureau of Indian Affairs (1959), data collected by Randich (1975), and a geologic map by Carlson (1978). The geology for Corson County was based on soil maps prepared by the U.S. Bureau of Indian Affairs (1959) and unpublished maps of the U.S. Soil Conservation Service, modified by test drilling and field reconnaissance.

The following definitions were used for figure 5.

Alluvium, terrace, outwash, colluvium, eolian deposits, and buried-valley fill-- The small scale prevents differentiating these deposits on this map. Alluvium is water-laid material deposited on flood plains and valleys of rivers and streams. Most of the material is clay, silt, and fine sand but there is some coarser material. Terraces are older alluvial deposits that now are above the level of the flood plain because the stream has eroded its valley deeper since deposition of the sediment. Outwash was deposited in streams and lakes formed by melting glaciers. Maximum thickness of alluvium or outwash is less than 120 feet; of terraces, more than 50 feet. Colluvium is landslide and slumpage detritus, commonly deposited at the foot of the steep slopes. The material usually is fragments of shale, silt, and sand, but may include gravel or sandstone cobbles from terraces or sandstone beds capping higher benches or buttes. Deposits may exceed 100 feet in thickness. Eolian deposits are windblown material, mostly silt and fine sand, but include some clay and, in some areas, much medium sand. Deposits are as much as 20 feet thick, but a thin coating, as little as a fraction of an inch thick, overlies most of the area. Buried valley fill is mostly glacial stream and outwash deposits but includes some till. The material is mostly moderately-sorted gravel, sand, silt, and clay. Maximum thickness locally exceeds 300 feet. Quaternary Period.

Glacial till -- Deposited beneath or at the margins of the continental glaciers. The material is a heterogeneous mixture of sizes from clay to boulders. Maximum thickness probably is less than 40 feet. Quaternary Period.

Fort Union Formation -- Gray to buff interbedded very fine to medium-grained sandstone, siltstone, claystone, silty clay, and shale; thin carbonaceous or lignitic beds near the base. Contains three widely persistent sandstone beds. Maximum thickness is greater than 400 feet. Tertiary Period.

Hell Creek Formation -- Somber-colored, soft clay shale and buff to gray, weakly-cemented, coarse- to fine-grained sandstone and siltstone. Contains lignitic lenses and thin, black carbonaceous shale beds. Maximum thickness may be greater than 400 feet. Cretaceous Period.

Fox Hills Formation -- Dark- to light-gray silty and sandy clay, clayey silt, and very fine-grained sandstone; overlain, in Corson County, by dark-gray to yellowish-orange, weakly-cemented, very fine-grained sandstone. The upper part of the formation is a thinly-bedded sequence of clay, silt, and sand, that contains discontinuous beds of silica-cemented very fine-grained sandstone. Contacts between the Hell Creek and Pierre Shale are gradational. Maximum thickness is about 400 feet. Cretaceous Period.

Pierre Shale -- Gray to brown, tough, gummy to friable shale, noncalcareous to highly calcareous, contains widely persistent zones of bentonite and of iron manganese or limestone concretions. Where exposed at the surface, the top few feet commonly is weathered. Maximum thickness is about 1,400 feet. Cretaceous Period.