When was Clatsop County founded?

Clatsop County was founded in 1844, and named after Clatsop people.

What is the county seat of Clatsop County?

The county seat of Clatsop County is Astoria.

Is there an online parcel map for Clatsop County?

Yes. Clatsop County publishes a parcel map of 35,462 parcels, rated good enough here. You can click any parcel on it in Parcel Chart's free map, no sign-in needed.

Has Clatsop County's boundary or name changed?

Atlas of Historical County Boundaries records 12 changes for Clatsop County. Since then the Atlas of Historical County Boundaries records 8 later changes, chiefly involving Tillamook County, Columbia County and Pacific (Wash.) County.

Who issues building permits in Clatsop County?

The county's page on building permits: PERMITS & LICENSES. Inside a city or town, ask that city first.

Is my lot in a flood zone?

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

County · code 41007

Clatsop CountyOregon

Clatsop County is a county in Oregon, with its seat in Astoria. The county was formed in 1844 and named after the Clatsop people.

Founded1844
County seatAstoria
Named forClatsop people
Land area828 sq mi + 255 sq mi water
Population41,072 2020 Census
Parcels mapped35,462 checked 15 October 2026

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

Updated 19 October 2026

Census outline · seat marked

History

Founded in 1844

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

The Provisional Legislature of Oregon Territory authorized the creation of Clatsop County on June 22, 1844, presumably from portions of Tuality District (now Washington). The county experienced multiple boundary changes over its history, losing land to Yamhill in 1846 and to Tillamook in 1853, while gaining territory from Columbia County in 1885 and 1931.

Boundary changes from the Newberry Library, Atlas of Historical County Boundaries; the 5 that matter most are shown first.

1846
Lost territory Clatsop lost to Yamhill.
to Yamhill
11 December 1846 · Ore. Terr. Laws, general and local, 1843-1849, p. 7
1853
Lost territory Clatsop lost to creation of Tillamook.
to Tillamook
15 December 1853 · Ore. Terr. Special Laws, 1853, 5th reg. sess., p. 6
1870
Lost territory Clatsop lost to Tillamook.
to Tillamook
22 October 1870 · Ore. Laws 1870, 6th reg. sess., pp. 24-25
1885
Gained territory Clatsop gained from Columbia.
from Columbia
24 February 1885 · Ore. Special Laws 1885, 13th reg. sess., p. 324
1893
Gained territory Clatsop gained from Tillamook.
from Tillamook
20 February 1893 · Ore. Laws 1893, gen., 17th reg. sess., pp. 77-78

Show all 12 changes (7 more, mostly small adjustments)

1844
Changed Provisional Legislature of Oregon Territory authorized the creation of Clatsop, presumably from the northern and western portions of Tuality District (now Washington). Introduction and passage of the bill creating Clatsop appears only within the session minutes for the Journal of the Provisional Legislature (1844), and no act regarding its creation appears in the general or special laws. No boundary description for the new county is given. See 19 December 1845 for the first mappable description of Clatsop.
Tuality DistrictWashington
22 June 1844 · Holman, p. 25; Oregon Archives, p. 43
1845
Boundary clarified Clatsop defined for the first time making it possible to map its 22 June 1844 creation from Tuality District (now Washington). Clatsop boundary with Vancouver District (now Clark, Washington) redefined to run along the main channel of the Columbia River.
with Tuality Districtwith Washingtonwith Vancouver Districtwith Clarkno change
19 December 1845 · Ore. Terr. Laws, general and local, 1843-1849, pp. 36-37
1846
Lost territory Clatsop lost to Yamhill.
to Yamhill
11 December 1846 · Ore. Terr. Laws, general and local, 1843-1849, p. 7
1852
Changed Pacific (Washington) fully organized, detached from Clatsop.
Pacific (Wash.)
28 January 1852 · Ore. Terr. Special Laws 1852, 4th reg. sess., p. 40
1853
Lost territory Clatsop lost to creation of Tillamook.
to Tillamook
15 December 1853 · Ore. Terr. Special Laws, 1853, 5th reg. sess., p. 6
1855
Boundary clarified Clatsop redefined; gained from Tillamook, lost to Columbia and Washington.
with Tillamook with Columbia with Washingtonno change
15 January 1855 · Ore. Terr. Special Laws 1854, 6th reg. sess., p. 33
1870
Lost territory Clatsop lost to Tillamook.
to Tillamook
22 October 1870 · Ore. Laws 1870, 6th reg. sess., pp. 24-25
1885
Gained territory Clatsop gained from Columbia.
from Columbia
24 February 1885 · Ore. Special Laws 1885, 13th reg. sess., p. 324
1891
Boundary clarified Clatsop boundaries redefined, lost to Tillamook.
with Tillamookno change
20 February 1891 · Ore. Laws 1891, gen., 16th reg. sess., pp. 102-103
1893
Gained territory Clatsop gained from Tillamook.
from Tillamook
20 February 1893 · Ore. Laws 1893, gen., 17th reg. sess., pp. 77-78
1931
Gained territory Clatsop gained from Columbia when boundary was redefined to run along range line.
from Columbia
6 March 1931 · Ore. Laws 1931, gen., 36th reg. sess., ch. 289/p. 515
1931
Boundary clarified Clatsop boundaries redefined (no change).
no change
11 March 1931 · Ore. Laws 1931, gen., 36th reg. sess., ch. 344/p. 600

Land and parcels

What the maps cover in Clatsop

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

Parcels Good enough

Lot lines and tax-map numbers for 35,462 parcels from Clatsop County. Drawn for tax purposes: usually within a few feet of a survey, but not a survey.
checked 15 October 2026
Address points Official

One point per address, 23,587 in all from State of Oregon — Department of Administrative Services Geospatial Enterprise Office (GEOHub) with Oregon Department of Emergency Management 9-1-1 program.
edited 16 January 2026 · checked 13 October 2026
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

Clatsop by the Census

Population

41,072 2020 Census count

Housing units

23,017 2020 Census count

Land area

828 square miles

Water area

255 square miles

People per sq mi

50 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.

Permits

PERMITS & LICENSESfrom clatsopcounty.gov

County government

County government
The official website of Clatsop County.
co.clatsop.or.us

See your own lot on these maps

Open Clatsop 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 Clatsop County

When was Clatsop County founded?: Clatsop County was founded in 1844, and named after Clatsop people.
What is the county seat of Clatsop County?: The county seat of Clatsop County is Astoria.
Is there an online parcel map for Clatsop County?: Yes. Clatsop County publishes a parcel map of 35,462 parcels, rated good enough here. You can click any parcel on it in Parcel Chart's free map, no sign-in needed.
Has Clatsop County's boundary or name changed?: Atlas of Historical County Boundaries records 12 changes for Clatsop County. Since then the Atlas of Historical County Boundaries records 8 later changes, chiefly involving Tillamook County, Columbia County and Pacific (Wash.) County.
Who issues building permits in Clatsop County?: The county's page on building permits: PERMITS & LICENSES. Inside a city or town, ask that city first.
Is my lot in a flood zone?: We do not have flood maps for Clatsop County yet. Look up the address on FEMA's Flood Map Service Center, which shows the effective flood map for any lot.

Nearby