County GIS · State lines · October 19, 2026
Maryland–Virginia Border Counties: Parcel Maps on Both Sides
All 18 counties on the Maryland–Virginia line, with seats, 2023 populations and a link to each official parcel map, plus what changes at the state line.
Looking for the counties on the Maryland–Virginia border and their parcel maps? According to the Census Bureau's county adjacency file, 8 Maryland counties touch 9 Virginia counties and 1 independent city along the line. Each one keeps its own property records and its own parcel viewer, so land near the line often means checking two counties in two states.
A farm, hunting tract or lake lot can sit in one state while the road, the neighbors or the rest of the property are in the other. This page lists every county that touches the line on either side, with links to each official parcel map.
Maryland–Virginia border at a glance
- Counties on the line: 18 (8 in Maryland, 10 in Virginia)
- With a verified public parcel viewer in our directory: 18 of 18
- Residents, 2023 estimates: about 2,821,443 on the Maryland side and 2,715,896 on the Virginia side
- Most populous on each side: Montgomery County, MD (1,058,474) and Fairfax County, VA (1,141,878)
- Largest by land area: Frederick County, MD (661 sq mi) and Loudoun County, VA (516 sq mi)
Maryland counties on the line
| County | Seat | Land (sq mi) | 2023 pop. | Parcel viewer |
|---|---|---|---|---|
| Charles County | La Plata | 458 | 171,973 | Maryland FINDER Online (MD Dept. of Planning) |
| Frederick County | Frederick | 661 | 293,391 | Maryland FINDER Online (MD Dept. of Planning) |
| Montgomery County | Rockville | 493 | 1,058,474 | ArcGIS Experience Builder |
| Prince George's County | Upper Marlboro | 483 | 947,430 | county web map |
| Somerset County | Princess Anne | 320 | 24,910 | Maryland FINDER Online (MD Dept. of Planning) |
| St. Mary's County | Leonardtown | 359 | 115,281 | Maryland FINDER Online (MD Dept. of Planning) |
| Washington County | Hagerstown | 458 | 155,813 | Maryland FINDER Online (MD Dept. of Planning) |
| Worcester County | Snow Hill | 468 | 54,171 | Maryland FINDER Online (MD Dept. of Planning) |
Virginia counties on the line
| County | Seat | Land (sq mi) | 2023 pop. | Parcel viewer |
|---|---|---|---|---|
| Accomack County | Accomac | 449 | 33,239 | county web map |
| Arlington County | — | 26 | 234,162 | county web map |
| City of Alexandria | — | 15 | 155,230 | county web map |
| Fairfax County | Fairfax | 391 | 1,141,878 | county web map |
| King George County | King George | 180 | 28,568 | ArcGIS Experience Builder |
| Loudoun County | Leesburg | 516 | 436,347 | county web map |
| Northumberland County | Heathsville | 191 | 12,391 | InteractiveGIS |
| Prince William County | Manassas | 335 | 489,640 | county web map |
| Stafford County | Stafford | 269 | 165,428 | ArcGIS Web AppBuilder |
| Westmoreland County | Montross | 229 | 19,013 | ArcGIS Map Viewer |
Which counties face each other
The Census adjacency file pairs counties that share a boundary. Use it to find the county across the line from the one you know:
- Charles County, MD borders Fairfax County, VA, King George County, VA, Prince William County, VA, Stafford County, VA, Westmoreland County, VA
- Frederick County, MD borders Loudoun County, VA
- Montgomery County, MD borders Arlington County, VA, Fairfax County, VA, Loudoun County, VA
- Prince George's County, MD borders City of Alexandria, VA, Fairfax County, VA
- Somerset County, MD borders Accomack County, VA, Northumberland County, VA
- St. Mary's County, MD borders Northumberland County, VA, Westmoreland County, VA
- Washington County, MD borders Loudoun County, VA
- Worcester County, MD borders Accomack County, VA
What changes when you cross the line
- Different viewers. On the Maryland side the official maps run on: Maryland FINDER Online (MD Dept. of Planning) (6); ArcGIS Experience Builder (1); county web map (1). On the Virginia side: county web map (6); ArcGIS Experience Builder (1); InteractiveGIS (1); ArcGIS Web AppBuilder (1); ArcGIS Map Viewer (1). Search boxes, parcel ID formats and the details shown in pop-ups will differ.
- Different records offices. Deeds, plats and tax bills are kept by the county where the parcel sits.
- Different rules. Zoning, septic permits and property tax are set locally and by each state, so check with the county on the side where you plan to build or buy.
Researching a tract that crosses the line
- Find the parcel in both counties' viewers. Each side will show only its own piece, with its own parcel number.
- Pull the recorded deed from each county's register or recorder, since each county records only the land inside its own boundary.
- Expect two tax bills, one from each county, and check each state's rules for homestead or farm exemptions.
- For a sale, a fence or a building permit, hire a licensed surveyor familiar with the line; tax-map lines are drawings, not surveys.
A quick way to check which side a spot is on
Open the Platbookmapper Land Map, search the nearest county, and tap the spot. The land report shows which county it falls in, along with flood zone, elevation, soil and wetlands, and links to that county's parcel map.
Related guides
- Maryland county GIS websites by viewer
- Maryland plat maps
- Virginia county GIS websites by viewer
- Virginia plat maps
More: Maryland counties · Virginia counties
Sources
- U.S. Census Bureau county adjacency file, used for which counties share the line.
- U.S. Census Bureau Gazetteer files, 2020 county land area.
- U.S. Census Bureau, Population Estimates Program, county totals, Vintage 2023 (July 1, 2023 estimates)
- Platbookmapper county GIS directory (live data file behind our county pages, pulled October 19, 2026) for each county's official parcel viewer.
- County seats: Wikidata (county seat property), cross-checked against Census place names.