When was Columbia County founded?

Columbia County was founded in 1875, formed from Walla Walla County, and named after Columbia River.

What is the county seat of Columbia County?

The county seat of Columbia County is Dayton.

Is there an online parcel map for Columbia County?

Yes. A public source publishes a parcel map of 5,484 parcels, rated good enough here. You can click any parcel on it in Parcel Chart's free map, no sign-in needed.

Has Columbia County's boundary or name changed?

Columbia County was created in 1875 from Walla Walla County. Since then the Atlas of Historical County Boundaries records 3 later changes, chiefly involving Garfield County and Walla Walla County.

Who issues building permits in Columbia County?

The county's page on building permits: 2005-04 Building Permit Fee Schedule. Inside a city or town, ask that city first.

Who issues septic and well permits in Columbia County?

The county's page on septic systems and wells: Public Health.

Is my lot in a flood zone?

We do not have flood maps for Columbia County yet. Look up the address on FEMA's Flood Map Service Center, which shows the effective flood map for any lot.

County · code 53013

Columbia CountyWashington

Columbia County is a county in Washington, with its seat in Dayton. It was formed on November 11, 1875, from Walla Walla County and was named after the Columbia River.

Founded1875
County seatDayton
Named forColumbia River
Land area869 sq mi + 4.9 sq mi water
Population3,952 2020 Census
Parcels mapped5,484 checked 15 October 2026

Open the free map Click any parcel in Columbia County: acreage, parcel id, address and who publishes the map. No sign-in.

Updated 20 October 2026

Census outline · seat marked

History

Formed in 1875 from Walla Walla County

An old deed may name a county that no longer exists, or a boundary that has since moved.

Columbia County was created in 1875 from Walla Walla County by Washington Territory. It lost territory to Walla Walla County in 1879 and to the creation of Garfield County in 1881. When Washington became a state in 1889, Columbia County continued as a Washington county.

Boundary changes from the Newberry Library, Atlas of Historical County Boundaries.

1875
Columbia County created Columbia created by Washington Territory from Walla Walla.
from Walla Walla
11 November 1875 · Wash. Terr. Laws 1875, 5th biennial sess., pp. 133-135
1879
Lost territory Columbia lost to Walla Walla.
to Walla Walla
13 November 1879 · Wash. Terr. Laws 1879, 7th biennial sess., p. 226
1881
Lost territory Columbia lost to creation of Garfield.
to Garfield
29 November 1881 · Wash. Terr. Laws 1881, 8th biennial sess., pp. 175-177
1889
Became part of Washington Columbia continued as a Washington county when the state of Washington admitted to the Union and Washington Territory eliminated. 11 November 1889 · U.S. Stat., vol. 25, ch. 180[1889], p. 676; U.S. Stat. pres. proc., vol. 26[1889], p. 10; Van Zandt, 155-156

Land and parcels

What the maps cover in Columbia

Who publishes each layer, how good it is, and when we last checked.

Parcels Good enough

Lot lines and tax-map numbers for 5,484 parcels. Drawn for tax purposes: usually within a few feet of a survey, but not a survey.
edited 30 September 2026 · checked 15 October 2026
Address points Missing

No public address points layer found for Columbia County yet.
Buildings Reference

Roof outlines traced from aerial imagery from FEMA Response Geospatial Office with Oak Ridge National Laboratory (ORNL). Good for seeing what is on a lot; not accurate enough to set a fence from.
checked 18 October 2026

Official: from the office that keeps the record
Good enough: a reliable statewide or national copy
Fallback: a guide only; check the official record
Missing: nothing public found yet

People and land

Columbia by the Census

Population

3,952 2020 Census count

Housing units

2,190 2020 Census count

Land area

869 square miles

Water area

4.9 square miles

People per sq mi

5 population ÷ land area

Source: US Census Bureau, 2020 Census; US Census Bureau, 2020 Gazetteer Files. Not endorsed or certified by the Census Bureau.

Rules and offices

Who to ask before you build, dig or sell

Official county pages only. We link to them; we do not copy them, because they change.

Inside a city or town, permits usually come from that city rather than the county.

Records

Assessor and property recordsfrom columbiaco.com · checked 13 October 2026
Clerk of court: deeds and platsfrom columbiaco.com · checked 13 October 2026

Permits

Health department: septic and well
Public Health
from columbiaco.com · checked 13 October 2026
2005-04 Building Permit Fee Schedulefrom columbiaco.com
Sign Permitfrom columbiaco.com

Zoning and code

Planning and zoningfrom columbiaco.com · checked 13 October 2026
2002-01 Amendment of Ordinance 2001-01from columbiaco.com
2002-02 Replacement of Ordinance 1994-06from columbiaco.com
2019-06 Zoning of the Columbia County Codefrom columbiaco.com
2017-03 Revising Titles 17 Subdivisions and 18 Zoningfrom columbiaco.com

County government

County government
The official website of Columbia County.
columbiaco.com

See your own lot on these maps

Open Columbia County on Parcel Chart's free map and click your parcel. Save it with a free account; the full record of your place (site map, projects, documents) is Pro, in early access.

Open the free map no sign-in Pro early access

Questions

Common questions about Columbia County

When was Columbia County founded?: Columbia County was founded in 1875, formed from Walla Walla County, and named after Columbia River.
What is the county seat of Columbia County?: The county seat of Columbia County is Dayton.
Is there an online parcel map for Columbia County?: Yes. A public source publishes a parcel map of 5,484 parcels, rated good enough here. You can click any parcel on it in Parcel Chart's free map, no sign-in needed.
Has Columbia County's boundary or name changed?: Columbia County was created in 1875 from Walla Walla County. Since then the Atlas of Historical County Boundaries records 3 later changes, chiefly involving Garfield County and Walla Walla County.
Who issues building permits in Columbia County?: The county's page on building permits: 2005-04 Building Permit Fee Schedule. Inside a city or town, ask that city first.
Who issues septic and well permits in Columbia County?: The county's page on septic systems and wells: Public Health.
Is my lot in a flood zone?: We do not have flood maps for Columbia County yet. Look up the address on FEMA's Flood Map Service Center, which shows the effective flood map for any lot.

Nearby