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Mapping FAQ's


What  is a GPIN? 
The Grid Parcel Identification Number (GPIN) is a unique 10-digit number that represents an x, y coordinate on the Prince William County proprietary grid. GPINs are calculated using GIS software. Each time the boundary of a parcel changes, a new GPIN is calculated, reflecting the new center of the parcel. The parcel's history can then be tracked using it's "parent" GPIN.
Because the GPIN is a coordinate identifier rather than a hierarchical identifier, the number is not related to size or any other characteristics of the polygons and gives no information about what subdivision a parcel belongs to or what parcel it was created from. That information is derived from related tables describing the subdivision and the parent-parcel.
Any parcel separated by a road and/or having noncontiguous polygons for any reason is still considered a single parcel and is assigned one GPIN. However, each polygon associated with that parcel will be assigned an individual centroid.
GPINs can be used to quickly locate the parcel on a County map or within County applications. GPINs link data between many County agencies, therefore, in order for the County to provide information to customers in a seamless environment, a GPIN is required before issuing permits.
Creating new parcels begins with the review of proposed development plans. Addresses are assigned to each proposed parcel during the review process. Once the approved plan/plat is recorded at the courthouse, a copy is forwarded to our office and the Geographic Information System (GIS) is updated with the parcel information and the new GPIN is created. This process may take several weeks to complete after which the information is available in the County's GIS database.

How do I find the GPIN for my property?
You can find the GPIN for your property by using the online County Mapper application. Just enter the parcel's address into the County Mapper and it will return information about that address (including the GPIN). 
There are also help pages available at the County Mapper site to assist you in conducting a number of operations using that service.

Can I get a copy of my plat?
The GIS Office has most subdivision plats on file. A subdivision plat shows every lot in the subdivision but does not show buildings or their dimensions. You can visit the GIS office at Suite 140 - 5 County Complex Court to purchase copies of subdivision plats.
Please note that the GIS office does not have copies of individual house location surveys/plats. A house location survey shows the boundary of the parcel/land and the house location/dimensions. It shows the distance from property edges to the house and can be used to figure the length of the house. If you need a house location survey, try one of the following resources:
  • Your lender/mortgage company,
  • The surveyor that was used for settlement,
  • Your settlement papers,
  • The settlement attorney, or
  • Title company that handled the sales transaction.

What other maps of my property are available?
The GIS Office offers parcel maps at a scale of 1" = 100', 200', 300' or 500'. Prices vary depending on the scale and number of data layers requested on the map. You can view a sample GPIN-centered map with aerial photography overlaid. Pricing and other map products can be viewed at our Complete Map Product List.
You can visit our office at Suite 140 - 5 County Complex Court to purchase map products. If you have an account with us, requests for GPIN-centered maps may be taken by FAX using the GPIN-centered map order form. Click the link to set up an account.

Where can I get aerial photographs of Prince William County?
The Prince William County GIS Office keeps an archive of aerial photographs for customer use. The 1937, 2004, 2006, 2008, 2009, 2011, 2013, and 2015 aerial photography are available using the online County Mapper application. The years 1954 to 1997 are not available online. Customers are welcome to conduct research of imagery in this date range at the office at 5 County Complex Court, Suite 140, from 8 a.m. to 4 p.m. Monday through Friday (Directions). We recommend that customers bring a digital camera as reproductions cannot be made of the maps.

Effective April 2014, Prince William County GIS will no longer sell digital orthophotography tiles for 2002 through 2015. Imagery may be obtained at no cost through the Virginia Geospatial Information Network (VGIN) as true color and infrared services made available for use:


Can I use a credit card to purchase my data or map products?
At this time, the GIS Office does not accept credit card payments. Payment must be made in cash or check. For customers who purchase products on a regular basis may choose to set up an account to be billed monthly.

Can I find the owner of property in Prince William County?
Property ownership information is provided by the Real Estate Assessments office. You may contact them directly at 703-792-6780 if you already know the property address, or you can visit their Real Property Assessment Information website. To obtain the property address, please contact the GIS Office and provide one of the following pieces of information:
  • The Legal Description
  • The Grid Parcel Identification Number (GPIN)
  • The old tax map number (if applicable)

What is Geographic Information System (GIS)?
A Geographic Information System (GIS) allows the user to capture, store, integrate, manipulate, analyze and display spatial and tabular information about the world as a collection of thematic layers that can be linked together by geography. Patterns, relationship and trends can be visualized that cannot otherwise be seen in a table or list format. This simple but extremely powerful and versatile concept has proven to be invaluable for solving many problems from developing school bus routes, to recording details of land development, to modeling future transportation needs.

How are addresses created?
New addresses are assigned to new parcels as development occurs. Addresses can be changed when problems, such as the following, arise:
    • Streets are renamed
    • Address numbers are duplicated
    • Address numbers are out of sequence
    • Driveway locations are on corner lots
When addresses are changed, notification is mailed to all property owners involved or affected by the change. Notification is also sent to County agencies, utility companies, and post offices.  
For more information on addressing, go to the addressing main page or contact our office at 703-792-6840.

What are Service Authority Address Listings?
Address listings for new developments must accompany any requests for a Utility Permit. Utility Permit fees and Tap fees cannot be paid until this form is received by Engineering at Prince William County Service Authority.
Addresses are assigned during the review of proposed development plans. This information is then provided to the developer. The developer must type the addresses onto the Service Authority Address Listing form once the plan is approved. 
The completed address listing may be sent to the GIS Office for verification via hand delivery, fax, or mail. The address verification process requires one business day, after which, the listing, with the original approval signature, is available for pickup at the GIS Customer Service counter. The Service Authority requires the original signature on the approval sheet and will not accept facsimiles.

What is the difference between a parcel address and a premise address?
Parcel addresses are assigned to a single piece of land. Premise addresses are assigned to buildings and/or units that are located on a parcel of land.  In cases where the parcel of land contains a single structure that is owner-occupied, the parcel address and premise address are the same. In cases where many structures are located on the same parcel (such as apartment complexes or business parks), the premise address will be different than the parcel address.


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