The Fairfax County tax map grid divides the county into approximately 444 tiles. This is the basis for the parcel numbering system in Fairfax County.

This table contains the assessed values for current tax year and prior tax year for land and building for properties in Fairfax County. There is a one to one relationship to the parcel data. Refer to this document for descriptions of the data in the table.

This table contains information about commercial properties including number of stories, elevators, exterior wall type, floor type and roof type for commercial properties within Fairfax County. There is a one to many relationship to the parcel data. Refer to this document for descriptions of the data in the table.

This layer contains the boundaries of special tax areas as defined by the taxing authority of Fairfax County. These are special tax districts where additional fees are levied on the properties within the districts. For current tax rates on properties for each of the tax areas refer to this page: https://www.fairfaxcounty.gov/taxes/real-estate/tax-rates Contact: Fairfax County Department of Information Technology GIS DivisionData Accessibility: Publicly AvailableUpdate Frequency: DailyLast Revision Date: 1/1/2000Creation Date: 1/1/2000Feature Dataset Name: GISMGR.PARCELSLayer Name: GISMGR.SPECIAL_TAX_AREAS

This table contains the information about the land including land sizes (square feet & acres) and land property type for properties within Fairfax County. There is a one to many relationship to the parcel data. Refer to this document for descriptions of the data in the table.

This table contains property sales information including sale date, price, and amounts for properties within Fairfax County. There is a one to many relationship to the parcel data. Refer to this document for descriptions of the data in the table.

This table contains information about additions to the structures such as patios, decks, porches, etc. for properties within Fairfax County. There is a one to many relationship to the parcel data. Refer to this document for descriptions of the data in the table.

The Chesapeake Bay Preservation Ordinance was adopted to protect our local streams and one of the world's most productive estuaries, the Chesapeake Bay, from pollution due to land use and development. All of Fairfax County drains into the Potomac River and ultimately the Chesapeake Bay. In an effort to protect and improve the quality of these waterways, sensitive areas along streams throughout Fairfax County have been designated as Resource Protection Areas.State regulations require that Resource Protection Areas (RPAs) be designated around all water bodies with perennial flow. Perennial flow means that water always flows in the stream or other water body except during periods of drought. The Department of Public Works and Environmental Services conducted field studies to identify all perennial streams throughout the county and used this information to prepare a set of maps showing the location of RPAs as defined under the revised Ordinance. The maps were adopted by the Board on November 17, 2003. The data include the boundaries of the RPAs adopted by the Board in 1993 and the additional RPAs adopted by the Board in 2003. These are general locations of RPA boundaries for planning purposes and the actual limits may be further refined by detailed field studies conducted at the time a plan is submitted to obtain a permit to develop a property.Any areas within Fairfax County not contained within the RPAs are Resource Management Areas (RMAs). Together, the RPAs and RMAs comprise the Chesapeake Bay Preservation Areas.

This table contains the legal description information including legal address (site address), deeded land area, and tax district for properties within Fairfax County. There is a one to one relationship to the parcels data. Refer to this document for descriptions of the data in the table.

This layer contains data defining the exterior boundaries of subdivided land within Fairfax County, Virginia. The Subdivision layer was created to depict subdivided land areas defined by recorded documents (plats) for the County of Fairfax. The polygons portrayed on this layer define the second portion of the County's Parcel Identification Numbering system (Map / Subdivision / Block / Parcel). Information portrayed on this layer was initially derived from the ink-on-mylar property maps maintained by the County since the early 1960s.For more information go to the Geospatial Property Data Guide.Contact: Fairfax County Department of Information Technology GIS DivisionData Accessibility: Publicly AvailableUpdate Frequency: DailyLast Revision Date: 1/1/2000Creation Date: 1/1/2000Feature Dataset Name: GISMGR.PARCELSLayer Name: GISMGR.SUBDIVISIONS

This layer contains data defining the exterior boundaries of land under common ownership, typically within condominium properties within Fairfax County, Virginia. The common area layer was created to depict these areas of land that do not actually have parcel identification numbers. These areas of land are owned by a group of properties that lie within the common area. Information portrayed on this layer was initially derived from the ink-on-mylar property maps maintained by the County since the early 1960s. Contact: Fairfax County Department of Information Technology GIS DivisionData Accessibility: Publicly AvailableUpdate Frequency: DailyLast Revision Date: 1/1/2000Creation Date: 1/1/2000Feature Dataset Name: GISMGR.PARCELSLayer Name: GISMGR.COMMON_AREAS

This table contains information about the parcel including livable units, land use code, zoning, and utility description for properties in Fairfax County. There is a one to many relationships to parcels data. Refer to this document for descriptions of the data in the table.

This layer contains data defining the exterior boundaries of subdivided land within subdivisions in Fairfax County, Virginia. The Block layer was created to depict subdivided land areas within subdivisions defined by recorded documents (plats) for the County of Fairfax. The polygons portrayed on this layer define the third portion of the County's Parcel Identification Numbering system (Map / Subdivision / Block / Parcel). Blocks are indicated on the property maps using a number within a single circle and boundaries that have heavy dashed lines. Information portrayed on this layer was initially derived from the ink-on-mylar property maps maintained by the County since the early 1960s.For more information go to the Geospatial Property Data Guide.Contact: Fairfax County Department of Information Technology GIS DivisionData Accessibility: Publicly AvailableUpdate Frequency: DailyLast Revision Date: 1/1/2000Creation Date: 1/1/2000Feature Dataset Name: GISMGR.PARCELSLayer Name: GISMGR.BLOCKS

More MetadataAt the July 3, 2012 Loudoun Board of Supervisor's Business Meeting, the Board agreed to be a funding partner with the Metropolitan Washington Airports Authority (MWAA) and Fairfax County for the Phase II extension of Metrorail to Dulles Airport and Ashburn. Loudoun County’s rail service districts were established on December 5, 2012 to fund the construction and maintenance of the stations, rail line, and rail related facilities and services. All parcels in the districts, residential and commercial, have a special property tax rate for funding of the rail. Tax collection for the districts is for Tax Year 2013 and future years.The boundaries of the Metrorail Service District were defined using physical features such as major roads and streams within two miles of stations. In some cases, parcel boundaries were used to develop the tax district boundary. The Route 606/Airport and Route 772 station service districts were defined using half-mile radii around the four proposed rail stations in or near Loudoun County: 1) Route 772, 2) Route 606, 3) Dulles Airport, and 4) Route 28. These radii were used as approximate guidelines. At the time the districts were established, the districts encompassed primarily commercial land. Only a few existing residential units were included within these districts at the time the districts were established.The features the boundaries follow may have been generalized due to scale and intended use.

Floodplain delineations were first added to the County tax maps in the 1970's for creeks and streams with watersheds of 1 square mile or greater. In 1977 all the studies on these large streams had been completed and a "Floodplain Overlay District" was created. Within several years this floodplain overlay district was depicted on the zoning maps. Again, these delineations were only for those creeks with drainage areas of over 1 square mile. A note in a 1981 memo to the Mapping Division about these delineations said, "...the County delineation of a Flood Plain Overlay District line on the tax map is treated here as a flag or general indicator of approximate location of this District's line. Normal development provides 2 field run topography professionally certified on which the floodplain elevations can be more accurately determined..." In 1985 the Zoning Ordinance was amended, an entire section on floodplains was added to Chapter 2 and the definition of what constituted a floodplain was significantly revised. Where as the Floodplain Overlay District had principally contained only those overbank areas inundated by the 100-yr storm along streams with drainage areas of 1 square mile or greater (i.e. 640 acres), the new definition included the overbank areas inundated by the 100-year storm along creeks with drainage areas of 70 acres and greater. But this change in the definition of floodplain created a problem for those who had become dependent on the tax maps to show them whether or not there was floodplain on a given property. These newly-defined floodplains were not yet studied or mapped and would only be mapped one property at a time, as each parcel containing these smaller floodplains submitted plans for development. When such parcels were developed, floodplain studies were required, and floodplain easements (later titled "floodplain and storm drainage easements") were recorded around these smaller floodplains. And as those easements were recorded, they were added to the tax maps. For all the floodplains which have been studied since 1985, the limits of the floodplain and storm drainage easements have been added to the tax maps, when such easements were required by the County Code or the Zoning Ordinance. But if a parcel has not yet been developed or if it was developed prior to 1985, there is usually no easement around the floodplain. There are also numerous cases where, for some reason, floodplain easements were recorded along small creeks with drainage areas well below 70 acres. These recorded "floodplain" easements were then added to the tax maps. THE RESULT: The tax maps cannot be used to definitively determine whether floodplain exists on a given parcel .There are approximately 900 miles of streams which meet the 70 acre drainage area requirement for floodplains, but to date (6/2003) almost 400 of these 900 miles remain unstudied. And if a stream has never been studied, no easement would have been recorded and thus the fact that it was a floodplain would not be reflected in the tax maps. Only after a determination of the drainage area is made can one know whether the overbank areas along a given creek meet the Zoning Ordinance definition of floodplain. Further if the drainage area is over 70 acres, only a floodplain study can determine the limits of the floodplain that is, how much of the overbank areas are inundated by the peak flow of the 100-yr storm. The layer for floodplains with drainage areas of over 1 square mile is good, but above that, it's inconsistent, especially in those areas which are minor floodplains (i.e. less than 360 acres of drainage area) and which were developed prior to 1985. The entire 850 or so miles of floodplain have not been mapped as unbroken corridors. And the "floodplain" here in Fairfax County, we're using the zoning ordinance definition which is the 100-yr water surface limits along streams with drainage areas of over 70 acres. This definition came into the zoning ordinance in 1985, so from that time, developers have had to study and map even these smaller floodplains on their developments and put them in easements. These easements have been captured on our tax maps since 1985, development by development, as the record plats were recorded. FEMA doesn't recognize as Special Flood Hazard Areas, many stream valleys that we would call floodplain. The layer currently on the data loader for floodplains is missing many segments of stream that are defined as floodplain per the zoning ordinance. Yet because of our zoning ordinance definition, this layer extends up in many areas far beyond where FEMA has mapped its 100-yr floodplains.Contact: Fairfax County Department of Information Technology GIS DivisionData Accessibility: Publicly availableUpdate Frequency: DailyLast Revision Date: 1/1/2000Creation date: 1/1/2000Dataset Name: GISMGR.ENCUMBRANCESLayer name: GISMGR.FLOOD_PLAIN_RECORDED

Loudoun County was founded in 1757. Loudoun's boundary with Maryland is the mean low water mark of the Potomac River on the Virginia side; it has not been surveyed. Loudoun's boundary with Prince William County is the Bull Run Creek. The border has not been modified for recent surveys. Individual plats along the Potomac and Bull Run Rivers have not resulted in a change in the border along those rivers- since measurements of the waters edge vary seasonally and the County Boundary needs to be seamless and constant. Many decades ago tax commissioners from surrounding jurisdictions assigned parcels to one jurisdiction or another rather than splitting parcels. Currently there is a mix of parcels split by a County Boundary, parcels taxed entirely in Loudoun, and portions of parcels within the County but taxed by another jurisdiction. The Office of the Commissioner of the Revenue dictates how these parcels are taxed, as do other jurisdictions. In 1957, the boundary with Fairfax County was re-established and finalized. The boundary with Fauquier County was surveyed and monumented in 1966. The boundary with Clarke County was surveyed in 1989, and the boundary survey with Jefferson County West Virginia was completed in 1998. The West Virginia, Fairfax, Fauquier, and Clarke boundary arcs were created by generating coverages from the monument coordinates using the generate command.