County GIS · State lines · October 19, 2026
Oregon–Washington Border Counties: Parcel Maps on Both Sides
All 21 counties on the Oregon–Washington 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 Oregon–Washington border and their parcel maps? According to the Census Bureau's county adjacency file, 10 Oregon counties touch 11 Washington counties 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.
Below you will find every county on both sides of the line, who borders whom, and what changes when you cross from one records office to the other.
Oregon–Washington border at a glance
- Counties on the line: 21 (10 in Oregon, 11 in Washington)
- With a verified public parcel viewer in our directory: 21 of 21
- Residents, 2023 estimates: about 1,038,764 on the Oregon side and 1,004,960 on the Washington side
- Most populous on each side: Multnomah County, OR (789,698) and Clark County, WA (521,150)
- Largest by land area: Umatilla County, OR (3,215 sq mi) and Klickitat County, WA (1,872 sq mi)
Oregon counties on the line
| County | Seat | Land (sq mi) | 2023 pop. | Parcel viewer |
|---|---|---|---|---|
| Clatsop County | Astoria | 828 | 41,102 | ORMAP statewide tax lot viewer |
| Columbia County | St. Helens | 659 | 53,880 | ORMAP statewide tax lot viewer |
| Gilliam County | Condon | 1,205 | 2,026 | ORMAP statewide tax lot viewer |
| Hood River County | Hood River | 522 | 23,745 | ORMAP statewide tax lot viewer |
| Morrow County | Heppner | 2,031 | 12,302 | ORMAP statewide tax lot viewer |
| Multnomah County | Portland | 431 | 789,698 | ORMAP statewide tax lot viewer |
| Sherman County | Moro | 824 | 1,951 | ORMAP statewide tax lot viewer |
| Umatilla County | Pendleton | 3,215 | 80,053 | ORMAP statewide tax lot viewer |
| Wallowa County | Enterprise | 3,146 | 7,674 | ORMAP statewide tax lot viewer |
| Wasco County | The Dalles | 2,381 | 26,333 | ORMAP statewide tax lot viewer |
Washington counties on the line
| County | Seat | Land (sq mi) | 2023 pop. | Parcel viewer |
|---|---|---|---|---|
| Asotin County | Asotin | 636 | 22,549 | ArcGIS Web AppBuilder |
| Benton County | Prosser | 1,700 | 215,219 | county web map |
| Clark County | Vancouver | 628 | 521,150 | county web map |
| Columbia County | Dayton | 869 | 4,053 | ArcGIS Instant Apps |
| Cowlitz County | Kelso | 1,141 | 112,864 | ArcGIS Experience Builder |
| Garfield County | Pomeroy | 711 | 2,363 | Washington Current Parcels layer in ArcGIS Map Viewer |
| Klickitat County | Goldendale | 1,872 | 23,589 | Washington Current Parcels layer in ArcGIS Map Viewer |
| Pacific County | South Bend | 934 | 24,200 | Washington Current Parcels layer in ArcGIS Map Viewer |
| Skamania County | Stevenson | 1,658 | 12,640 | Washington Current Parcels layer in ArcGIS Map Viewer |
| Wahkiakum County | Cathlamet | 263 | 4,765 | ArcGIS Experience Builder |
| Walla Walla County | Walla Walla | 1,270 | 61,568 | Washington Current Parcels layer in 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:
- Clatsop County, OR borders Pacific County, WA, Wahkiakum County, WA
- Columbia County, OR borders Clark County, WA, Cowlitz County, WA, Wahkiakum County, WA
- Gilliam County, OR borders Klickitat County, WA
- Hood River County, OR borders Klickitat County, WA, Skamania County, WA
- Morrow County, OR borders Benton County, WA, Klickitat County, WA
- Multnomah County, OR borders Clark County, WA, Skamania County, WA
- Sherman County, OR borders Klickitat County, WA
- Umatilla County, OR borders Benton County, WA, Columbia County, WA, Walla Walla County, WA
- Wallowa County, OR borders Asotin County, WA, Columbia County, WA, Garfield County, WA
- Wasco County, OR borders Klickitat County, WA
What changes when you cross the line
- Different viewers. On the Oregon side the official maps run on: ORMAP statewide tax lot viewer (10). On the Washington side: Washington Current Parcels layer in ArcGIS Map Viewer (5); county web map (2); ArcGIS Experience Builder (2); ArcGIS Web AppBuilder (1); ArcGIS Instant Apps (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
More: Oregon counties · Washington 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.