The Washington DC Area geologic map database (DCDB) provides geologic map information of areas to the NW, W, and SW of Washington, DC to various professionals and private citizens who have uses for geologic data. Digital, geographically referenced, geologic data is more versatile than traditional hard copy maps, and facilitates the examination of relationships between numerous aspects of the geology and other types of data such as: land-use data, vegetation characteristics, surface water flow and chemistry, and various types of remotely sensed images. The DCDB was created by combining Arc/Info coverages, designing a Microsoft (MS) Access database, and populating this database. Proposed improvements to the DCDB include the addition of more geochemical, structural, and hydrologic data.

This app displays a series of general information for an address, location, or where the user clicks in DC.Some information returned are:-Municipal Separate Storm Sewer System (MS4) area-Combined Sewer System (CSS) area-Watershed, Subwatershed, HUC12, HUC14, HUC16-Ward, ANC, SMD, and the address of the location-Census Tract and zip codeFor addresses along the borders of watersheds and sewer areas, further investigation should be taken. For hydrologic calculations and determinations, the USGS Watershed Boundary Dataset (WBD) should be referenced.DC Water operates a "separate" (MS4) and "combined" (CSS) sewers. Since the early 1900's, sewers constructed within the District have been separate systems and no new combined sewer systems have been built. These two independent piping systems: CSS mixes "sanitary" (sewage from homes and businesses) with stormwater while the MS4 is for "stormwater" only. In the District, approximately two thirds of the District is served by the MS4. The remaining one-third is served by the CSS. Areas highlighted in blue are MS4, in orange are CSS, and in green are direct drain areas that drain directly to streams and rivers. The MS4 system discharges into portions of the Potomac, Anacostia and Rock Creek drainage areas. The CSS drains to Blue Plains Advance Wastewater Treatment Facility.Visit DOEE - Water in the District Page or DOEE Environmental Mapping.For the USGS Hydrologic and Watershed Boundary Data for DC, visit this Link.Created with the Information Lookup Template from ESRIhttps://dcgis.maps.arcgis.com/home/item.html?id=54da82ed8d264bbbb7f9087df8c947c3

The dataset includes polygons representing the location and attributes of Central Employment Area (CEA). The CEA is the core area of the District of Columbia where the greatest concentration of employment in the city and region is encouraged, created as part of the DC Geographic Information System (DC GIS) for the D.C. Office of the Chief Technology Officer (OCTO) and participating D.C. government agencies. Jurisdictions were identified from public records (map and written description created by the National Capital Planning Commission) and heads-up digitized from the 1995 orthophotographs.

The database for the Washington West 30- by 60-minute quadrangle covers an area of approximately 4,884 square kilometers (1,343 square miles) in and west of the Washington, D.C., metropolitan area. The eastern part of the area is highly urbanized, and more rural areas to the west are rapidly being developed. The area lies entirely within the Chesapeake Bay drainage basin and mostly within the Potomac River watershed. It contains part of the Nation's main north-south transportation corridor east of the Blue Ridge Mountains, consisting of Interstate Highway 95, U.S. Highway 1, and railroads, as well as parts of the Capital Beltway and Interstate Highway 66. Extensive Federal land holdings in addition to those in Washington, D.C., include the Marine Corps Development and Education Command at Quantico, Fort Belvoir, Vint Hill Farms Station, the Naval Ordnance Station at Indian Head, the Chesapeake and Ohio Canal National Historic Park, Great Falls Park, and Manassas National Battlefield Park. The quadrangle contains most of Washington, D.C.; part or all of Arlington, Culpeper, Fairfax, Fauquier, Loudoun, Prince William, Rappahannock, and Stafford Counties in northern Virginia; and parts of Charles, Montgomery, and Prince Georges Counties in Maryland. The Washington West quadrangle spans four geologic provinces. From west to east these provinces are the Blue Ridge province, the early Mesozoic Culpeper basin, the Piedmont province, and the Coastal Plain province. There is some overlap in ages of rocks in the Blue Ridge and Piedmont provinces. The Blue Ridge province, which occupies the western part of the quadrangle, contains metamorphic and igneous rocks of Mesoproterozoic to Early Cambrian age. Mesoproterozoic (Grenville-aged) rocks are mostly granitic gneisses, although older meta-igneous rocks are found as xenoliths. Small areas of Neoproterozoic metasedimentary rocks nonconformably overlie Mesoproterozoic rocks. Neoproterozoic granitic rocks of the Robertson River Igneous Suite intruded the Mesoproterozoic rocks. The Mesoproterozoic rocks are nonconformably overlain by Neoproterozoic metasedimentary rocks of the Fauquier and Lynchburg Groups, which in turn are overlain by metabasalt of the Catoctin Formation. The Catoctin Formation is overlain by Lower Cambrian clastic metasedimentary rocks of the Chilhowee Group. The Piedmont province is exposed in the east-central part of the map area, between overlapping sedimentary units of the Culpeper basin on the west and those of the Coastal Plain province on the east. In this area, the Piedmont province contains Neoproterozoic and lower Paleozoic metamorphosed sedimentary, volcanic, and plutonic rocks. Allochthonous mélange complexes on the western side of the Piedmont are bordered on the east by metavolcanic and metasedimentary rocks of the Chopawamsic Formation, which has been interpreted as part of a volcanic arc. The mélange complexes are unconformably overlain by metasedimentary rocks of the Popes Head Formation. The Silurian and Ordovician Quantico Formation is the youngest metasedimentary unit in this part of the Piedmont (Pavlides and others, 1980). Igneous rocks include the Garrisonville Mafic Complex, transported ultramafic and mafic inclusions in mélanges, monzogranite of the Dale City pluton, and Ordovician tonalitic and granitic plutons. Jurassic diabase dikes are the youngest intrusions. The fault boundary between rocks of the Blue Ridge and Piedmont provinces is concealed beneath the Culpeper basin in this area but is exposed farther south (Mixon and others, 2000). Early Mesozoic rocks of the Culpeper basin unconformably overlie those of the Piedmont and Blue Ridge provinces in the central part of the quadrangle. The north-northeast-trending extensional basin contains Upper Triassic to Lower Jurassic nonmarine sedimentary rocks. Lower Jurassic sedimentary strata are interbedded with basalt flows, and both Upper Triassic and Lower Jurassic strata are intruded by diabase of Early Jurassic age. The Bull Run Mountain fault, a major Mesozoic normal fault characterized by down-to-the-east displacement, separates rocks of the Culpeper basin from those of the Blue Ridge province on the west. On the east, the contact between rocks of the Culpeper basin and those of the Piedmont province is an unconformity which has been locally disrupted by normal faults. Sediments of the Coastal Plain province unconformably overlie rocks of the Piedmont province along the Fall Zone and occupy the eastern part of the quadrangle. Lower Cretaceous deposits of the Potomac Formation consist of fluvial-deltaic gravels, sands, silts, and clays. Discontinuous fluvial and estuarine terrace deposits of Pleistocene and middle to late Tertiary age flank the modern Potomac River valley unconformably capping these Cretaceous strata and the crystalline basement where the Cretaceous has been removed by erosion. East of the Potomac River, the Potomac Formation is onlapped and unconformably overlain by a westward thinning wedge of marine sedimentary deposits of Late Cretaceous and early and late Tertiary age. Basement rooted Coastal Plain faults of Tertiary to Quaternary age occur along the Fall Zone and this part of the inner Coastal Plain. These Coastal Plain faults have geomorphic expression that appear to influence river drainage patterns (Mixon and others, 1972; Seiders and Mixon, 1981; Fleming and others, 1994).

Wooded areas captured in 1999. Contract NCPC 93-02. This document describes the planimetric map production for the 350 tiles located in Washington DC and the surrounding states of MD and VA.

This historic 1936 zoning map was digitized and georeferenced to Washington, D.C. It is from the Washingtoniana Map Collection at the District of Columbia Public Library’s DIG DC site. The 1936 map depicts the 1920 regulations amended to 1936 and was published for the DC Zoning Commission by Rufus Lusk. This map breaks the residential zone into six different categories regulating the type of housing allowed in an area. This map also includes regulations on residential lot occupancy. It is used in the Office of Zoning's Historic Web Viewer . More information this map and other content found on the DC Public Library DIG DC website .

Generalized Policy from the Comprehensive Plan Amendment Act of 2010, effective April 8, 2011.This data set is part of the Comprehensive Plan of the District of Columbia. It categorizes how different parts of the District may change by 2025. It highlights areas where more detailed Comprehensive Plan policies have been provided to manage this change. These policies may generally be found in the ten Area Elements. This dataset should be used to guide land use decision-making in conjunction with the Comprehensive Plan text, the Future Land Use Map, and other Comprehensive Plan maps. Boundaries within the dataset are to be interpreted in conjunction with these other resources in addition to the information shown here.

These are the ten planning areas created by the Office of Planning to serve as a static subdivision of the city and allow for analysis across long-term time scales. Unlike election ward boundaries or other political divisions, these areas are intended to remain unchanged and stable. The polygons first appeared in comprehensive plan documents to represent planning areas known as 'Area Elements.'

This EnviroAtlas dataset describes the total counts and percentage of population, land area, and impervious surface in the 1% Annual Chance Flood Hazard area or 0.2% Annual Chance Flood Hazard area of each block group. The flood hazard area is defined by the National Flood Hazard Layer (NFHL) produced by the Federal Emergency Management Agency (FEMA, www.fema.gov). This dataset was produced by the US EPA to support research and online mapping activities related to EnviroAtlas. EnviroAtlas (https://www.epa.gov/enviroatlas) allows the user to interact with a web-based, easy-to-use, mapping application to view and analyze multiple ecosystem services for the contiguous United States. The dataset is available as downloadable data (https://edg.epa.gov/data/Public/ORD/EnviroAtlas) or as an EnviroAtlas map service. Additional descriptive information about each attribute in this dataset can be found in its associated EnviroAtlas Fact Sheet (https://www.epa.gov/enviroatlas/enviroatlas-fact-sheets).

The TIGER/Line Files are shapefiles and related database files (.dbf) that 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 File is designed to stand alone as an independent data set, or they can be combined to cover the entire nation. Face refers to the areal (polygon) topological primitives that make up MTDB. A face is bounded by one or more edges; its boundary includes only the edges that separate it from other faces, not any interior edges contained within the area of the face. The Topological Faces Shapefile contains the attributes of each topological primitive face. Each face has a unique topological face identifier (TFID) value. Each face in the shapefile includes the key geographic area codes for almost all geographic areas for which the Census Bureau tabulates data for both the 2010 Census and Census 2000. The geometries of each of these geographic areas can then be built by dissolving the face geometries on the appropriate key geographic area codes in the Topological Faces Shapefile.

Geology was researched and compiled for use in studies of ecosystem health, environmental impact, soils, groundwater, land use, tectonics, crustal genesis, sedimentary provenance, and any others that could benefit from geographically referenced geological data.

The Washington DC Area geologic map database (DCDB) provides geologic map information of areas to the NW, W, and SW of Washington, DC to various professionals and private citizens who have uses for geologic data. Digital, geographically referenced, geologic data is more versatile than traditional hard copy maps, and facilitates the examination of relationships between numerous aspects of the geology and other types of data such as: land-use data, vegetation characteristics, surface water flow and chemistry, and various types of remotely sensed images. The DCDB was created by combining Arc/Info coverages, designing a Microsoft (MS) Access database, and populating this database. Proposed improvements to the DCDB include the addition of more geochemical, structural, and hydrologic data.

Data are provided in several common GIS formats and MS Access database files. The geologic data themes included are bedrock, surficial, faults and fold axes, neat line, structural data, and sinkholes; the base themes are political boundaries, roads, elevation contours, and hydrography.

Data were originally collected in UTM coordinates, zone 18, NAD 1927, and projected to geographic coordinates (Lat/Long), NAD 1983. The data base is accompanied by large format color maps, a readme.txt file, and a explanatory PDF pamphlet.

This EnviroAtlas dataset describes the breakdown of the land cover classes with each Census Block Group. In this commmunity, forest is defined as Trees & Forest, and Woody Wetlands. Green space is defined as Trees & Forest, Grass & Herbaceous, Agriculture, Woody Wetlands, and Emergent Wetlands. Agriculture is defined as Agriculture alone.Wetlands are defined as Woody Wetlands and Emergent Wetlands. This dataset also includes the area per capita for each block group for some land cover types. This dataset was produced by the US EPA to support research and online mapping activities related to EnviroAtlas. EnviroAtlas (https://res1wwwd-o-tepad-o-tgov.vcapture.xyz/enviroatlas) allows the user to interact with a web-based, easy-to-use, mapping application to view and analyze multiple ecosystem services for the contiguous United States. The dataset is available as downloadable data (https://res1edgd-o-tepad-o-tgov.vcapture.xyz/data/Public/ORD/EnviroAtlas) or as an EnviroAtlas map service. Additional descriptive information about each attribute in this dataset can be found in its associated EnviroAtlas Fact Sheet (https://res1wwwd-o-tepad-o-tgov.vcapture.xyz/enviroatlas/enviroatlas-fact-sheets).

A web map used for the Police Service Area Details web application.In addition to Police Districts, every resident lives in a Police Service Area (PSA), and every PSA has a team of police officers and officials assigned to it. Residents should get to know their PSA team members and learn how to work with them to fight crime and disorder in their neighborhoods. Each police district has between seven and nine PSAs. There are a total of 56 PSAs in the District of Columbia.Printable PDF versions of each district map are available on the district pages. Residents and visitors may also access the PSA Finder to easily locate a PSA and other resources within a geographic area. Just enter an address or place name and click the magnifying glass to search, or just click on the map. The results will provide the geopolitical and public safety information for the address; it will also display a map of the nearest police station(s).Each Police Service Area generally holds meetings once a month. To learn more about the meeting time and location in your PSA, please contact your Community Outreach Coordinator. To reach a coordinator, choose your police district from the list below. The coordinators are included as part of each district's Roster.Visit https://mpdc.dc.gov for more information.

This map presents land cover and detailed topographic maps for the United States. It uses the USA Topographic Map service. The map includes the National Park Service (NPS) Natural Earth physical map at 1.24km per pixel for the world at small scales, i-cubed eTOPO 1:250,000-scale maps for the contiguous United States at medium scales, and National Geographic TOPO! 1:100,000 and 1:24,000-scale maps (1:250,000 and 1:63,000 in Alaska) for the United States at large scales. The TOPO! maps are seamless, scanned images of United States Geological Survey (USGS) paper topographic maps.

The maps provide a very useful basemap for a variety of applications, particularly in rural areas where the topographic maps provide unique detail and features from other basemaps.

To add this map service into a desktop application directly, go to the entry for the USA Topo Maps map service.

Tip: Here are some famous locations as they appear in this web map, accessed by including their location in the URL that launches the map:

Grand Canyon, Arizona

Golden Gate, California

The Statue of Liberty, New York

Washington DC

Canyon De Chelly, Arizona

Yellowstone National Park, Wyoming

Area 51, Nevada

The Washington DC EnviroAtlas Meter-scale Urban Land Cover (MULC) dataset comprises an area of 5423.43 km2 encompassing the entire area of Washington DC, and portions of the state of Maryland and state of Virginia. These MULC data and maps were derived from 1-m pixel, four-band (red, green, blue, and infrared light) leaf-on aerial photography acquired from the United States Department of Agriculture (USDA) National Agriculture Imagery Program (NAIP) as well as ancillary data (e.g., Lidar, National Wetlands Inventory [NWI], cropland, land parcels, power lines, building footprints). Eight land cover classes were mapped: Water, Impervious Surfaces, Soil/Barren, Trees/Forest, Grass/Herbaceous, Agriculture, Woody Wetlands and Emergent Wetlands. Wetlands were delineated using the state wide wetlands data from National Wetlands Inventory (NWI) layer updated on October 15, 2018 (https://www.fws.gov/wetlands/Data/State-Downloads.html ). An analysis of 600 completely random and 111 stratified random photo-interpreted land cover reference points yielded a simple overall user's accuracy (MAX) of 85.4% and an overall fuzzy user's accuracy (RIGHT) of 91.5% within the census block group boundary (see confusion matrices below). These data were developed as part of the Chesapeake Bay High-Resolution Land Cover Project, a cooperative agreement between the Chesapeake Conservancy and the National Park Service, funded through an interagency agreement with the Environmental Protection Agency (EPA). The Chesapeake Conservancy, under the direction of Margaret Markham, created the initial statewide 1-meter land cover data. EPA added agriculture and wetlands taken from ancillary data sources. See detailed processing steps and workflow below. This dataset was produced by the Chesapeake Conservancy, the National Park Service, and the US EPA to support research and online mapping activities related to EnviroAtlas. EnviroAtlas (https://www.epa.gov/enviroatlas) allows the user to interact with a web-based, easy-to-use, mapping application to view and analyze multiple ecosystem services for the contiguous United States. The dataset is available as downloadable data (https://edg.epa.gov/data/Public/ORD/EnviroAtlas) or as an EnviroAtlas map service. Additional descriptive information about each attribute in this dataset can be found in its associated EnviroAtlas Fact Sheet (https://www.epa.gov/enviroatlas/enviroatlas-fact-sheets).

Named Landforms of the World version 2 (NLWv2) contains four sub-layers representing geomorphological landforms, provinces, divisions, and their respective cartographic boundaries. The latter supports map making, while the first three represent basic units, such as landforms, which comprise provinces, and provinces comprise divisions. NLW is a substantial update to World Named Landforms in both compilation method and the attributes that describe each landform. For more details, please refer to our paper, Named Landforms of the World: A Geomorphological and Physiographic Compilation, in Annals of the American Association of Geographers. July 2, 2025: We have made Named Landforms of the World v3 (NLWv3) available. Please explore this group containing all of the layers and data. NLWv2 will remain available. Landforms are commonly defined as natural features on the surface of the Earth. The National Geographic Society specifies terrain as the basis for landforms and lists four major types: mountains, hills, plateaus, and plains. Here, however, we define landforms in a richer way that includes properties relating to underlying geologic structure, erosional and depositional character, and tectonic setting and processes. These characteristics were asserted by Dr. Richard E. Murphy in 1968 in his map, titled Landforms of the World. We blended Murphy"s definition for landforms with the work E.M. Bridges, who in his 1990 book, World Geomorphology, provided a globally consistent description of geomorphological divisions, provinces, and sections to give names to the landform regions of the world. AttributeDescriptionBridges Full NameFull name from E.M. Bridges" 1990 "World Geomorphology" Division and if present province and section - intended for labeling print maps of small extents. Bridges DivisionGeomorphological Division as described in E.M. Bridges" 1990 "World Geomorphology" - All Landforms have a division assigned, i.e., no nulls. Bridges ProvinceGeomorphological Province as described in E.M. Bridges" 1990 "World Geomorphology" - Not all divisions are subdivided into provinces. Bridges SectionGeomorphological Section as described in E.M. Bridges" 1990 "World Geomorphology" - Not all provinces are subdivided into sections.StructureLandform Structure as described in Richard E. Murphy"s 1968 "Landforms of the World" map. Coded Value Domain. Values include: - Alpine Systems: Area of mountains formed by orogenic (collisions of tectonic plates) processes in the past 350 to 500 million years. - Caledonian/Hercynian Shield Remnants: Area of mountains formed by orogenic (collisions of tectonic plates) processes 350 to 500 million years ago. - Gondwana or Laurasian Shields: Area underlaid by mostly crystalline rock formations fromed one billion or more years ago and unbroken by tectonic processes. - Rifted Shield Areas: fractures or spreading along or adjacent to tectonic plate edges. - Isolated Volcanic Areas: volcanic activity occurring outside of Alpine Systems and Rifted Shields. - Sedimentary: Areas of deposition occurring within the past 2.5 million years Moist or DryLandform Erosional/Depositional variable as described in Richard E. Murphy"s 1968 "Landforms of the World" map. Coded Value Domain. Values include: - Moist: where annual aridity index is 1.0 or higher, which implies precipitation is absorbed or lost via runoff. - Dry: where annual aridity index is less than 1.0, which implies more precipitation evaporates before it can be absorbed or lost via runoff. TopographicLandform Topographic type variable as described in Richard E. Murphy"s 1968 "Landforms of the World" map. Karagulle et. al. 2017 - based on rich morphometric characteristics. Coded Value Domain. Values include: - Plains: Areas with less than 90-meters of relief and slopes under 20%. - Hills: Areas with 90- to 300-meters of local relief. - Mountains: Areas with over 300-meters of relief - High Tablelands: Areas with over 300-meters of relief and 50% of highest elevation areas are of gentle slope. - Depressions or Basins: Areas of land surrounded land of higher elevation. Glaciation TypeLandform Erosional/Depositional variable as described in Richard E. Murphy"s 1968 "Landforms of the World" map. Values include: - Wisconsin/Wurm Glacial Extent: Areas of most recent glaciation which formed 115,000 years ago and ended 11,000 years ago. - Pre-Wisconsin/Wurm Glacial Extent: Areas subjected only to glaciation prior to 140,000 years ago. ContinentAssigned by Author during data compilation. Bridges Short NameThe name of the smallest of Division, Province, or Section containing this landform feature. Murphy Landform CodeCombination of Richard E. Murphy"s 1968 "Landforms of the World" variables expressed as a 3- or 4- letter notation. Used to label medium scale maps. Area_GeoGeodesic area in km2. Primary PlateName of tectonic plate that either completely underlays this landform feature or underlays the largest portion of the landform"s area.Secondary PlateWhen a landform is underlaid by two or more tectonic plates, this is the plate that underlays the second largest area.3rd PlateWhen a landform is underlaid by three or more tectonic plates, this is the plate that underlays the third largest area.4th PlateWhen a landform is underlaid by four or more tectonic plates, this is the plate that underlays the fourth largest area.5th PlateWhen a landform is underlaid by five tectonic plates, this is the plate that underlays the fifth largest area.NotesContains standard text to convey additional tectonic process characteristics. Tectonic ProcessAssigns values of orogenic, rift zone, or above subducting plate. These data are also available as an ArcGIS Pro Map Package: Named_Landforms_of_the_World_v2.0.mpkx.These data supersede the earlier v1.0: World Named Landforms. Change Log:DateDescription of ChangeJuly 20, 2022Corrected spelling of Guiana from incorrect representation, "Guyana", used by Bridges.July 27, 2022Corrected Structure coded value domain value, changing "Caledonian/Hercynian Shield" to "Caledonian , Hercynian, or Appalachian Remnants". Cite as: Frye, C., Sayre R., Pippi, M., Karagulle, Murphy, A., D. Soller, D.R., Gilbert, M., and Richards, J., 2022. Named Landforms of the World. DOI: 10.13140/RG.2.2.33178.93129. Accessed on:

These maps display the areas throughout the city that were impacted by the new school attendance zones as of SY2015-16. The area is considered impacted if it was reassigned to a different school or reassigned to just one of its current school options (previously some areas had rights to multiple schools due to school closures). These maps do not take into account phasing in policies. For more information about the 2014 Student Assignment and Boundaries Review Process, visit https://dme.dc.gov.

Census Tracts from 2020. The TIGER/Line shapefiles 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 tracts are small, relatively permanent statistical subdivisions of a county or equivalent entity, and were defined by local participants as part of the 2020 Census Participant Statistical Areas Program. The Census Bureau delineated the census tracts in situations where no local participant existed or where all the potential participants declined to participate. The primary purpose of census tracts is to provide a stable set of geographic units for the presentation of census data and comparison back to previous decennial censuses. Census tracts generally have a population size between 1,200 and 8,000 people, with an optimum size of 4,000 people. When first delineated, census tracts were designed to be homogeneous with respect to population characteristics, economic status, and living conditions. The spatial size of census tracts varies widely depending on the density of settlement. Physical changes in street patterns caused by highway construction, new development, and so forth, may require boundary revisions. In addition, census tracts occasionally are split due to population growth, or combined as a result of substantial population decline. Census tract boundaries generally follow visible and identifiable features. They may follow legal boundaries such as minor civil division (MCD) or incorporated place boundaries in some States and situations to allow for census tract-to-governmental unit relationships where the governmental boundaries tend to remain unchanged between censuses. State and county boundaries always are census tract boundaries in the standard census geographic hierarchy. In a few rare instances, a census tract may consist of noncontiguous areas. These noncontiguous areas may occur where the census tracts are coextensive with all or parts of legal entities that are themselves noncontiguous. For the 2020 Census, the census tract code range of 9400 through 9499 was enforced for census tracts that include a majority American Indian population according to Census 2010 data and/or their area was primarily covered by federally recognized American Indian reservations and/or off-reservation trust lands; the code range 9800 through 9899 was enforced for those census tracts that contained little or no population and represented a relatively large special land use area such as a National Park, military installation, or a business/industrial park; and the code range 9900 through 9998 was enforced for those census tracts that contained only water area.

The tidal shoreline buffer includes the areas along the banks of the Potomac and Anacostia Rivers that are projected to be inundated by tides on a daily basis by 2080. These areas are regulated under the DC Flood Hazard Rules. To calculate this area, DOEE used 3.4 feet as the expected amount of relative sea level rise between 2000 and 2080 which is the Intermediate-High Projection in 2080 from the 2022 NOAA Sea Level Rise Technical Report. 3.4 feet is added to 2.0 feet NAVD88 (which is mean higher high water in the year 2000) to arrive at the 5.4 foot NAVD88 elevation that sets the extent of the tidal shoreline buffer. Additional details and diagrams in presentation slides 5, 32-36:https://doee.dc.gov/sites/default/files/dc/sites/doee/publication/attachments/Flood%20Regulation%20Updates%202024-08-01%20Info%20Presentation.pdf

This EnviroAtlas dataset describes the percentage of forested, vegetated, and impervious land within 15- and 50-meters of hydrologically connected streams, rivers, and other water bodies within the EnviroAtlas community area. In this community, tree cover is defined as Trees & Forest, and Woody Wetlands. and In this community, vegetated land is defined as Trees & Forest, Grass & Herbaceous, Woody Wetlands, and Emergent Wetlands. This dataset was produced by the US EPA to support research and online mapping activities related to EnviroAtlas. EnviroAtlas (https://res1wwwd-o-tepad-o-tgov.vcapture.xyz/enviroatlas) allows the user to interact with a web-based, easy-to-use, mapping application to view and analyze multiple ecosystem services for the contiguous United States. The dataset is available as downloadable data (https://res1edgd-o-tepad-o-tgov.vcapture.xyz/data/Public/ORD/EnviroAtlas) or as an EnviroAtlas map service. Additional descriptive information about each attribute in this dataset can be found in its associated EnviroAtlas Fact Sheet (https://res1wwwd-o-tepad-o-tgov.vcapture.xyz/enviroatlas/enviroatlas-fact-sheets).