The U.S. inland navigation system consists of of rivers maintained by the Corps of Engineers in 22 states, and includes 276 lock chambers with a total lift of 6,100 feet. The highly adaptable and effective system of barge navigation moves over 625 million tons of commodities annually, which includes coal, petroleum products, various other raw materials, food and farm products, chemicals, and manufactured goods. The shallow draft waterways have many unique characteristics and difficulties over coastal harbor and ocean navigation; river levels can change by over 30 feet in a seasonal cycle, the navigation channel can shift significantly within the river banks, and shifting yet ever present river currents pose constant challenges in these confined waterways. Electronic chart systems can offer significant benefits to vessels including accurate and real-time display of vessel position relative to waterway features, voyage planning and monitoring, training tools for new personnel and integrated display of river charts, radar, and Automatic Identification Systems. Following recommendations by the National Transportation Safety Board, the National Academy of Science and the American Waterways Operators, Congress directed the Corps of Engineers to develop and publish electronic charts for the inland waterways. Development of Inland Electronic Navigational Charts (IENCs) to cover the Mississippi River and tributaries thus began in 2001 with pilot projects on the Atchafalaya River in Louisiana and Lower Mississippi River near Vicksburg, Mississippi. These projects, which involved a combination of in-house and contract activities, were the first efforts to collect and convert inland waterway data, commonly used for river and channel maintenance, into the international S-57 hydrographic data exchange. This highly structured data format is commonly used for electronic chart applications and will be used for Corps IENCs An S-57 database is extracted into an Esri File Geodatabase for publication. This is that geodatabase and it contains 99 feature classes that make up the IENC data. 2026-04-01T00:00:00 Army Geospatial Center IENC POC IENC_POC@usace.army.mil DATA_QUALITY_AREA Users should be aware that the IENCs reflect best available information at the time the data was collected. These data products are subject to change. USACE USCG IENC HIFLD Inland Electronic Navigation Charts Continental United States This geodatabase feature class is created as part of the publication of the IENC data. It is authoritative from the United States Army Corps of Engineers Inland Electronic Navigation Charts (USACE IENC) as of the date of publication. This data may be updated twice a month. A master feature service containing 92 of the 99 layers as feature services that can be exported and queried can be referenced in the Distribution information section. Note that seven of the services have modified symbology due to feature limitations. They are: DAM_LINE, FERRY, LEVEE_LINE, Overhead_Pipeline, RAILROAD, ROAD_LINE, SUBMARINE_PIPELINE. The six layers that were removed were: Building_Point, Buoy_Special_Purpose, Daymark, Depth_Area, Shoreline_Construction_Area, Shoreline_Construction_Line. Other download options are included in Distribution information. In addition to these options, KML, RSS, and GeoPDF data downloads can be found at: https://ienccloud.us/#DataDownload This page also contains up-to-date alternative geo-enabled formats found in other distribution options as well as an interactive browser map viewer and a viewer that visualizes individual chart coverage. Spelling, capitalization, abbreviation definitions, and formatting in dataset attribution comply with the Encoding Guide of Inland ENC (<http://ienccloud.us/ienc/products/files/documents/IENC%20Encoding%20Guide%20-%20Edition%202.3.6.pdf>). For example: 1) The mandatory source indicator is encoded under the following format (per page 13 of the encoding guide): 2 character country code, 2 character authority code, 5 character source code, identifier (no restriction on number of characters), e.g., (US,U3,SURVY,2001_Hydro_Survey). 2) Blank values indicate data that was not provided or otherwise not available; Denotes missing data that was not present in the source data. However, the missing data may be present in other sources not yet discovered and used in the creation and/or maintenance of this dataset. These records may be populated with valid information in future update cycles. Null values are not the same as blank values and may indicate values that were not translated from the original source charts. 3) Abbreviations and capitalization may reference a temporary status or a standard United States Coast Guard (USCG) Navigation Center entity (<https://www.navcen.uscg.gov/>; a recent light list containing abbreviations can be found at <https://www.navcen.uscg.gov/pdf/lightLists/LightList_V5_2020.pdf>). Additional common abbreviations are included in specific feature class field and supplemental information metadata. These occur in fields such as but not limited to Object_Name and Information in feature classes including but not limited to BUOY_SPECIAL_PURPOSE, CAUTION_AREA, CAUTION_AREA_POINT, DAYMARK, Lateral_Beacon, FLOODWALL, ISOLATED_DANGER_BUOY_POINT, LAND_REGION_POINT, LIGHTS, MOORING_FACILITY_POINT, Notice_Mark, PILE_POINT, PYLONS_AREA, SEA_AREA_POINT, SHORELINE_CONSTRUCTION_AREA, SHORELINE_CONSTRUCTION_LINE, SUBMARINE_PIPELINE_POINT, Lateral_Buoy, and RAILROAD. 4) In cases where units are not indicated in an entry that are encapsulated in parentheses, the units are assumed to be a mile marker referencing statute miles. These occur in fields such as but not limited to Object_Name and Information in feature classes in feature classes including but not limited to Bridge_Area, BUOY_SPECIAL_PURPOSE, CAUTION_AREA, CAUTION_AREA_POINT, CONVEYOR_AREA, FERRY, HARBOR_FACILITY_POINT, ISOLATED_DANGER_BUOY_POINT, LAND_REGION_POINT, Lateral_Beacon, LIGHTS, Lock_Basin, MOORING_FACILITY_AREA, MOORING_FACILITY_POINT, PILE_POINT, SEA_AREA_POINT, SHORELINE_CONSTRUCTION_AREA, SHORELINE_CONSTRUCTION_LINE, Traffic_Signal_Station, Warning_Signal_Station, Waterway_Gauge_Point, DAYMARK, Lateral_Buoy, and OBSTRUCTION_POINT. To query specific enumerations and definitions not included in this metadata, access an up to date, interactive IENC Feature Catalog at: http://ienccloud.us/ienc/web/s-57/index24.html. USACE IENC An area within which a uniform assessment of the quality of the data exists. Distinction: accuracy of data; survey reliability; The USACE IENCs coverage area consists of 7,260 miles across 21 rivers primarily located in the Central United States. IENCs apply to inland waterways that are maintained for navigation by USACE for shallow-draft vessels (e.g., maintained at a depth of 9-14 feet, dependent upon the waterway project authorization). Generally, IENCs are produced for those commercially navigable waterways which the National Oceanic and Atmospheric Administration (NOAA) does not produce Electronic Navigational Charts (ENCs). However, Special Purpose IENCs may be produced in agreement with NOAA. Users should be aware that the IENCs reflect best available information at the time the data was collected. These data products are subject to change. None (Public Domain Information) None (Public Domain Information) USCAPCO Map Service, KML, WMS, WFS, RSS, GeoPDF, Overlays https://ienccloud.us/arcgis/rest/services IENC Map Services Hosts Map Services, WFS, and WMS services by Chart and Feature Class for quick attribute review in web maps and ArcMap. Army Geospatial Center IENC POC IENC_POC@usace.army.mil https://services3.arcgis.com/JR1tf2VoTNNjWen5/arcgis/rest/services/USACE_IENC_HIFLD_Layers/FeatureServer IENC Hosted Feature Services Hosts a subset of the dataset (see supplemental information on which feature classes have limitations) as Feature Services by Feature Class for ArcMap detailed attribute access and dynamic exporting for offline use. MB 1.83 Army Geospatial Center IENC POC IENC_POC@usace.army.mil https://hifld-geoplatform.opendata.arcgis.com/ HIFLD Open The HIFLD Open homepage distributes this data from the map services and allows downloads and web service access in a variety of formats with additional descriptive information. MB 1.83 Army Geospatial Center IENC POC IENC_POC@usace.army.mil http://ienccloud.us/ienc/products/files/u37/ienc_master_dataset_gdb/USACE_IENC_Master_Service_gdb.zip Master Geodatabase The IENC Master Geodatabase downloads all 400,000+ features in all charts and datasets to a single geodatabase for offline use of the entire dataset suite. MB 131 Army Geospatial Center IENC POC IENC_POC@usace.army.mil File Geodatabase Feature Class ArcGIS ArcGISPro 3.3 Build 52636 Users should be aware that the IENCs reflect best available information at the time the data was collected. These data products are subject to change. Temporal Validity OBJECTID SHAPE Category_of_Zone_Confidence The CATZOC attribute definitions are currently the subject of review and the results of this review will be promulgated as soon as possible in the S-57 Corrections Document. See the CATZOC Table in S-57 for the full table layout. Inland Electronic Navigational Charts (IENC) Zones of confidence with value options including A1, A2, B, C, D, or U (not assessed). Technique_of_Sounding_Measurement Technique of sounding measurement. Inland Electronic Navigational Charts (IENC) Found by echo-sounder. The depth was determined by using an instrument that determines depth of water by measuring the time interval between emission of a sonic or ultrasonic signal and return of its echo from the bottom. (adapted from IHO Dictionary, S-32, 1547) Inland Electronic Navigational Charts (IENC) Found by side-scan-sonar. The depth was computed from a record produced by active sonar in which fixed acoustic beams are directed into the water perpendicularly to the direction of travel to scan the bottom and generate a record of the bottom configuration. (adapted from IHO Dictionary, S-32, 4710) Inland Electronic Navigational Charts (IENC) Found by multi-beam. The depth was determined by using a wide swath echo sounder that uses multiple beams to measure depths directly below and transverse to the ship's track. (adapted from IHO Dictionary, S-32, 3339) Inland Electronic Navigational Charts (IENC) Found by diver. The depth was determined by a person skilled in the practice of diving. (adapted from IHO Dictionary, S-32, 1422) Inland Electronic Navigational Charts (IENC) Found by lead-line. The depth was determined by using a line, graduated with attached marks and fastened to a sounding lead. (adapted from IHO Dictionary, S-32, 2698) Inland Electronic Navigational Charts (IENC) Swept by wire-drag. The given area was determined to be free from navigational dangers to a certain depth by towing a buoyed wire at the desired depth by two launches, or a least depth was identified using the same technique. (adapted from IHO Dictionary, S-32, 5248, 6013) Inland Electronic Navigational Charts (IENC) Found by laser. The depth was determined by using an instrument that measures distance by emitting timed pulses of laser light and measuring the time between emission and reception of the reflected pulses. (adapted from IHO Dictionary, S-32, 2763) Inland Electronic Navigational Charts (IENC) Swept by vertical acoustic system. The given area has been swept using a system comprised of multiple echo sounder transducers attached to booms deployed from the survey vessel. Inland Electronic Navigational Charts (IENC) Found by electromagnetic sensor. The depth was determined by using an instrument that compares electromagnetic signals. (adapted from IHO Dictionary, S-32, 1571) Inland Electronic Navigational Charts (IENC) Photogrammetry. The depth was determined by applying mathematical techniques to photographs. (adapted from IHO Dictionary, S-32, 3791) Inland Electronic Navigational Charts (IENC) Satellite imagery. The depth was determined by using instruments placed aboard an artificial satellite. (adapted from IHO Dictionary, S-32, 4509) Inland Electronic Navigational Charts (IENC) Found by levelling. The depth was determined by using levelling techniques to find the elevation of the point relative to a datum. (adapted from IHO Dictionary, S-32, 2741) Inland Electronic Navigational Charts (IENC) Swept by side-scan-sonar. The given area was determined to be free from navigational dangers to a certain depth by towing a side-scan-sonar. (adapted from IHO Dictionary, S-32, 5248, 4710) [415.2] Inland Electronic Navigational Charts (IENC) Computer Generated. The sounding was determined from a bottom model constructed using a computer. Inland Electronic Navigational Charts (IENC) Source_Date The production date of the source of the data (e.g. the date of measurement). The source date should be coded for those objects in an IENC, which are changing regularly, for example depth information. Inland Electronic Navigational Charts (IENC) Numeric calendar date. The format is yearmonthday (YYYYMMDD). For example, SORDAT coding for a feature with of source date of September 30, 2004 is 20040930. Inland Electronic Navigation Charts (IENC) 2 Source_Indication The source indicator is a mandatory attribute and must be coded for all objects in the IENC. All objects in the Encoding Guide state that SORIND is Conditional (C); the condition that must be met is that it is a US produced chart. Inland Electronic Navigational Charts (IENC) Per page 13 of the encoding guide (see supplemental information for link): Each entry contains 2 character country code, 2 character authority code, 5 character source code, identifier (no restriction on number of characters). For example, features reference an authority such as the USCG Mississippi River System Light List, Volume 5: (US,U3,MS_LL,2004_Edition_No.808). Source_Dataset Dataset or chart from which feature is derived. Homeland Infrastructure Foundation Level Data (HIFLD) Support Team (HST) 8 character encoded reference name for original chart indicating country, subdivision, state, and state subdivision. Feature_ID Feature Object Identifier field (FOID) Inland Electronic Navigational Charts (IENC) Numeric Feature S-57 ID SHAPE_Length SHAPE_Area 20260402 00443300 1.0 TRUE