Property or parcel data is a critical layer to any city. In DC's complex urban environment, this includes numerous geographies that identify federal government lands, reservations, District lands, personal property and so much more.

DC's Real Property Tax Administration defines assessment and taxation lots, often referred to as A&T lots or simply tax lots. These lots are strictly for real estate taxation purposes and normally defined under two circumstances: When property owners ask for their real property tax bills to be consolidated, after they have bought several contiguous record lots; this is called a combine;When part of a record lot is sold, but no new record lot is yet defined; this is called a split request. Tax lots are not determined by survey, and are therefore not official lots in the same way record lots are. These lots are normally numbered between 800 and 1999within a square to differentiate them from record lots on the property tax maps. When a tax lot is established by RPTA, an A&T Plat is generated by RPTA and forwarded to the surveyor’s office. These A&T Plats are not reviewed but simply filed by the Surveyor; they do not comply with the standards required of subdivision plats, and are not recorded. Tax Lots are not normally acceptable when applying for building permits and must be converted to Record Lots through the normal subdivision process involving the D.C. Surveyor’s Office before permits will be issued. The only exception is if the lot does not face a public street. Furthermore, at the time of their creation and platting, there is no review made of tax lots for compliance with D.C. Zoning, Subdivisions or any other ordinances. These lots are simply pieces of property, owned by somebody, described in deeds, for which tax bills are sent and real estate taxes are collected by the city. Some Record Lots also function in this capacity. Geographically, tax lots typically overlay layers such as record lots or sometimes reservations. There are known instances where tax lots do not overlay these types of layers. Up until approximately 1972, A&T lots were only created by the Tax Assessor out of lands that had been previously Record Lots at some point in their history. For a short period of time in the early to mid 1970’s, a decision was made to start eliminating fractional parcels (see definition below) and make them all into A&T lots. The intent was to do away with Parcels altogether and have all properties in the city be either tax lots or record lots. By doing this, they converted unsubdivided parcels into A&T lots where no underlying record lot exists. There is often little or no historical source information about these types of transactions therefore vectorizing them often required vast amounts of research.

These are lands still within the District of Columbia that has never been subdivided into either Record or Tax Lots through the two offices that manage land records (OS & RPTA), this land is referred to as Parcels, expressed as fractions (Ex Parcel 117/36). In this example, the number “36” would be the 36th out conveyance from original Parcel 117. The tracking of parcels was started in 1905 when, by Act of Congress, all the District’s unsubdivided properties which were mostly rural farms at the time were given parcel numbers. Their boundaries were also depicted (in many cases approximated), in large books in DCRA's Office of the Surveyor. Until the late 1960s, building permits were routinely issued by the city for new construction on Parcels, but today all Parcels, like Tax Lots, must be converted into subdivision Lots of Record before permits will be issued for exterior work. Parcels are only found in the old “County of Washington,” north of Florida Ave and east of the Anacostia River. There are no Parcels found within the original city limits or Georgetown. Parcels are not in Squares. There are examples where parcel land may be physically located in the middle of a city Square, but Parcels are not considered part of a Square until they are duly subdivided by the D.C. Surveyor’s Office.

The relationship between a property and an address is many-to-many. In DC a SSL (Square, Suffix, Lot) is used to identify a property. One SSL can have multiple addresses located on it. This often includes garden-style apartment complexes as well as corner buildings with separate addresses facing each adjacent street. One address can also sit upon multiple SSLs. One single family residence can sit upon multiple lots. The cross reference table contains the many-to-many relationship between address IDs and SSLs. [A small percentage of addresses do not have an associated SSL (such as metro entrances or many addresses on Federal property.] Use this cross reference table to relate the District's address points in the Master Address Repository (MAR) with the SSLs and vice versa.

The common ownership lots is a single polygon layer that is built from various polygon feature classes of the District's Vector Property Mapping database including the below. It represents all lands that are outside right-of-way.Record LotsTax LotsParcel LotsReservation LotsAir Rights LotsAll of which are found separately on https://opendata.dc.gov. The Office of Tax and Revenue maintains a database known as Information Tax System (ITS) that contains the accounts for the real property taxes. ITS records reference record lots, tax lots, parcels, condominiums and federally owned lands such as reservations. Information from ITS is conflated to Common Ownership Lot features by SSL (Square, Suffix and Lot). This layer does not include condo records. This layer is regenerated WEEKLY with an automated algorithm using the latest Pubic Extract information for attribution.

Property lots in DC are identified by their Square Suffix Lot number (SSL). SSL are 12 characters in length. The first 4 characters are your Square. The middle 4 characters, if present, are your Suffix and last 4 characters are your lot. Therefore, If Lot is numbered 1-799 it is a Record Lot. Exceptions to this rule are identified in this table. Furthermore, if Lot is numbered 800-1999 it is a Tax Lot If Lot number is 2000-6999 it is a Condo Lot If Lot is numbered 7000 or above it is a Air Rights Lot If it begins with PAR it is a Parcel If it begins with RES it is a Reservation

Record lots are defined by the Department of Buildings (DOB) – Office of the Surveyor (OS) - DC Surveyor. They are official, platted, recorded subdivision lots created by the D.C Surveyor’s Office in compliance with the Subdivision Ordinance of the District of Columbia (must have public street frontage etc). Typically, these lots are numbered 1 through 799 with no number being used more than once in a Square. Exceptions to this rule:When the 1-799 range has been exhausted within a square, the Surveyor’s Office assigns numbers from 1200 or may even use 8000 and aboveFor reasons unknown, 42 Squares have record lot numbers greater than 799 but less than 1200Additionally, in most case scenario’s, a piece of property must be a Record Lot before a building permit will be issued for that site in the District of Columbia, and all proposed Record Lots are carefully reviewed by Zoning Administration officials for compliance with the city’s Zoning Ordinances. Other agencies that review new record lots besides OS are Office of Zoning, Office of Planning, the Dept. of Public Works, Historic Preservation and DDOT.Record lots are defined only when requested by property owners, normally when they are seeking a building permit. Record lots are recorded in Plat Books and Subdivision Books in the Office of the Surveyor. These documents are bound volumes of historical representations of the locations of property lines, and they include record dimensions, though typically no bearings of lines. These lots are located within squares, which usually correspond to one or two city blocks. Certain record lots can also be classified as “of-lots”. An "Of-Lot" is the D.C. Surveyor’s Office term for describing “Remaining/Part of Original Lot X”In the record lot feature class, if a _domain value of 1 resides in the “OF_LOT” field, you can assume that at one time the original lot was modified. Typically, any of these of-lots will also have a tax lot overlaying them since it is a piece or remainder of a Record Lot.

Property or parcel data is a critical layer to any city. In DC's complex urban environment, this includes numerous geographies that identify federal government lands, reservations, District lands, personal property and so much more.

The dataset contains locations and attributes of owner lines with dimensions. The tax information (attribution) comes from the Office of Tax and Revenue's Public Extract file. The creation of this layer is automated, occurs weekly, and uses the most currently available tax information. The date of the extract can be found in the EXTRACTDAT field in this layer.

This layer is a subset of ITSPE and and UBIDs representing vacant and blighted property building footprints. The tax assessment roll public extract (ITSPE) is used for assessment and property analysis, to send property tax bills and notices, and stores comprehensive tax information such as ownership, mailing addresses, non-contiguous Air Rights lots (Multifamily or Development), Air Rights lots, possessory interest lots, record lots, tax lots, parcels, condominiums, and federally owned lands such as reservations and appropriations. The linkage from the Vector Property layers to this database is SSL (Square, Suffix, and Lot). The UBID data was originally created by spatially joining the 2019 building footprints published in DC Open Data with the Common Ownership Lots. The UBIDs were coded using US DOE’s Implementation code. Search for UBID and ITSPE in Open Data DC for individual documentation.

The interactive zoning map allows users to determine the zoning classification for any property in the District. Users can search zoning by specific address, square and lot, parcel, Zoning Commission (ZC) case, or Planned Unit Development (PUD), where applicable. Users can select different layers of data to display on the map, and can print reports for any selected property. Users should note that when searching for a PUD, the ZC case name and ZC case number reflect the most recent case name and case number associated with the PUD. If you have questions, comments, or suggestions regarding the zoning map, contact the Office of Zoning at (202) 727-6311 or dcoz@dc.gov.

Record lots are defined by the Department of Buildings (DOB) – Office of the Surveyor (OS) - DC Surveyor. They are official, platted, recorded subdivision lots created by the D.C Surveyor’s Office in compliance with the Subdivision Ordinance of the District of Columbia (must have public street frontage etc). Typically, these lots are numbered 1 through 799 with no number being used more than once in a Square. Exceptions to this rule:When the 1-799 range has been exhausted within a square, the Surveyor’s Office assigns numbers from 1200 or may even use 8000 and aboveFor reasons unknown, 42 Squares have record lot numbers greater than 799 but less than 1200Additionally, in most case scenario’s, a piece of property must be a Record Lot before a building permit will be issued for that site in the District of Columbia, and all proposed Record Lots are carefully reviewed by Zoning Administration officials for compliance with the city’s Zoning Ordinances. Other agencies that review new record lots besides OS are Office of Zoning, Office of Planning, the Dept. of Public Works, Historic Preservation and DDOT.Record lots are defined only when requested by property owners, normally when they are seeking a building permit. Record lots are recorded in Plat Books and Subdivision Books in the Office of the Surveyor. These documents are bound volumes of historical representations of the locations of property lines, and they include record dimensions, though typically no bearings of lines. These lots are located within squares, which usually correspond to one or two city blocks. Certain record lots can also be classified as “of-lots”. An "Of-Lot" is the D.C. Surveyor’s Office term for describing “Remaining/Part of Original Lot X”In the record lot feature class, if a domain value of 1 resides in the “OF_LOT” field, you can assume that at one time the original lot was modified. Typically, any of these of-lots will also have a tax lot overlaying them since it is a piece or remainder of a Record Lot.

Record lots are defined by the Department of Buildings (DOB) – Office of the Surveyor (OS) - DC Surveyor. They are official, platted, recorded subdivision lots created by the D.C Surveyor’s Office in compliance with the Subdivision Ordinance of the District of Columbia (must have public street frontage etc). Typically, these lots are numbered 1 through 799 with no number being used more than once in a Square. Exceptions to this rule:When the 1-799 range has been exhausted within a square, the Surveyor’s Office assigns numbers from 1200 or may even use 8000 and aboveFor reasons unknown, 42 Squares have record lot numbers greater than 799 but less than 1200Additionally, in most case scenario’s, a piece of property must be a Record Lot before a building permit will be issued for that site in the District of Columbia, and all proposed Record Lots are carefully reviewed by Zoning Administration officials for compliance with the city’s Zoning Ordinances. Other agencies that review new record lots besides OS are Office of Zoning, Office of Planning, the Dept. of Public Works, Historic Preservation and DDOT.Record lots are defined only when requested by property owners, normally when they are seeking a building permit. Record lots are recorded in Plat Books and Subdivision Books in the Office of the Surveyor. These documents are bound volumes of historical representations of the locations of property lines, and they include record dimensions, though typically no bearings of lines. These lots are located within squares, which usually correspond to one or two city blocks. Certain record lots can also be classified as “of-lots”. An "Of-Lot" is the D.C. Surveyor’s Office term for describing “Remaining/Part of Original Lot X”In the record lot feature class, if a domain value of 1 resides in the “OF_LOT” field, you can assume that at one time the original lot was modified. Typically, any of these of-lots will also have a tax lot overlaying them since it is a piece or remainder of a Record Lot.

This table is a subset of ITSPE and represents vacant and blighted property. The tax assessment roll public extract (ITSPE) is used for assessment and property analysis, to send property tax bills and notices, and stores comprehensive tax information such as ownership, mailing addresses, non-contiguous Air Rights lots (Multifamily or Development), Air Rights lots, possessory interest lots, record lots, tax lots, parcels, condominiums, and federally owned lands such as reservations and appropriations. The linkage from the Vector Property layers to this database is SSL (Square, Suffix, and Lot). It should be noted that not all record lots have a direct 1:1 relationship to information in this database. The most obvious examples would be when a tax lot was created from existing record lots. In this case, only the tax lot would have linkage to the ITSPE, not the underlying record lots (though they still exist). Reservations that have been converted into tax lots are an additional example where the reservation still exists, however for taxation purposes the tax lot (overlay) supersedes and has corresponding linkage to ITS. The same is true for most Condominiums and the ground surface lot (Record) which still exist (common space) or the previous overlay (Air Right or Tax lot), only the Condo lot would have linkage to (ITSPE).

The dataset contains locations and attributes of owner lines with dimensions, 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. The tax information (attribution) comes from OTR's Public Extract file. The creation of this layer is automated, occurs weekly, and uses the most currently available tax information. The date of the extract can be found in the EXTRACTDATE field in this layer.

🇺🇸 미국 English Record lots are defined by the Department of Buildings (DOB) – Office of the Surveyor (OS) - DC Surveyor. They are official, platted, recorded subdivision lots created by the D.C Surveyor’s Office in compliance with the Subdivision Ordinance of the District of Columbia (must have public street frontage etc). Typically, these lots are numbered 1 through 799 with no number being used more than once in a Square. Exceptions to this rule:When the 1-799 range has been exhausted within a square, the Surveyor’s Office assigns numbers from 1200 or may even use 8000 and aboveFor reasons unknown, 42 Squares have record lot numbers greater than 799 but less than 1200Additionally, in most case scenario’s, a piece of property must be a Record Lot before a building permit will be issued for that site in the District of Columbia, and all proposed Record Lots are carefully reviewed by Zoning Administration officials for compliance with the city’s Zoning Ordinances. Other agencies that review new record lots besides OS are Office of Zoning, Office of Planning, the Dept. of Public Works, Historic Preservation and DDOT.Record lots are defined only when requested by property owners, normally when they are seeking a building permit. Record lots are recorded in Plat Books and Subdivision Books in the Office of the Surveyor. These documents are bound volumes of historical representations of the locations of property lines, and they include record dimensions, though typically no bearings of lines. These lots are located within squares, which usually correspond to one or two city blocks. Certain record lots can also be classified as “of-lots”. An "Of-Lot" is the D.C. Surveyor’s Office term for describing “Remaining/Part of Original Lot X”In the record lot feature class, if a domain value of 1 resides in the “OF_LOT” field, you can assume that at one time the original lot was modified. Typically, any of these of-lots will also have a tax lot overlaying them since it is a piece or remainder of a Record Lot.

This dataset represents parcels not mapped or sourced in Vector Property Map. Please refer to the common ownership lots layer in https://opendata.dc.gov for the most current data on ownership. Property Owner Points. This dataset contains points that represent the approximate location of real property lots within the District of Columbia. Each property point is generated based on a corresponding record maintained within the Office of Tax and Revenue (OTR) Real Property Tax Administration's (RPTA) real property database. Each point contains the full attribution of database fields derived from ITS public release extract. The initial data conversion effort was begun in 1997 as a means to provide RPTA with a digital mapping system which could be maintained to reflect ongoing changes to property lots and ownership. The initial step was to scan RPTA tax square maps from aperture cards at an effective paper resolution of 400 DPI. The resulting images were then georeferenced to DC's 0.2-meter resolution 1995 digital orthophotos. During the georeferencing process, the images were not warped; they were simply scaled and rotated to best fit the orthophotos. The DC tax assessor provided a database of active tax accounts which were placed interactively by an operator using the georeferenced square image and the orthophoto. Centroids were placed on the primary structure visible in the orthophoto within the raster property polygon. The placement was performed within ArcView 3.2 using a customized data production application. Accounts which could not be placed in the first pass were then reviewed by another operator to attempt to find their correct location. The placed points were QC'd through a spatial overlay with the square index to assure a match between the square field value within the property database and the actual square polygon into which the point was placed. Spot checking was then performed to confirm that the centroids fell within the correct raster lot. The centroids were delivered to OTR as a single citywide AutoCAD DWG file. Attribute features with square, suffix, and lot numbers (SSLs) were included as an AutoCAD block.

This layer is a component of Property_and_Land.

Provided by the Office of the Chief Technology Officer

© DC GIS

Property and parcel data is a critical layer to any city or statewide data holdings. In our city's complex urban environment, this includes numerous geographies that identify federal government lands, reservations, District lands, personal property and so much more. Use this application to query and identify boundaries including,Property LotsLot DimensionsCondo DataTax AssessmentsZoningSquaresThe District's Vector Property Mapping (VPM) project works daily to capture property lot transactions so that city planners, business development leaders and residents stay current.

The Office of the Chief Technology Officer (OCTO), Office of Tax and Revenue (OTR)Real Property Tax Administration (RPTA), and Department of Consumer and Regulatory Affair's (DCRA) Surveyor's Office (OS) manage the vector property map data.