When was Polk County founded?

Polk County was founded in 1845, and named after James K. Polk.

What is the county seat of Polk County?

The county seat of Polk County is Dallas.

Is there an online parcel map for Polk County?

Not that we have found yet. Lot lines and owners of record are kept by the county assessor's office. When a public parcel map appears, it shows here.

Has Polk County's boundary or name changed?

Polk County was created in 1845. Since then the Atlas of Historical County Boundaries records 5 later changes, chiefly involving Tillamook County, Benton County and Lincoln County.

Who issues building permits in Polk 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 Polk County yet. Look up the address on FEMA's Flood Map Service Center, which shows the effective flood map for any lot.

County · code 41053

Polk CountyOregon

Polk County is a county in Oregon with its seat in Dallas, created in 1845.

Founded1845
County seatDallas
Named forJames K. Polk
Land area741 sq mi + 3.2 sq mi water
Population87,433 2020 Census

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

Updated 20 October 2026

Census outline · seat marked

History

Founded in 1845

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

Polk County was created by the Provisional Legislature of Oregon Territory on December 22, 1845. The county was named after James K. Polk. Polk became an Oregon county when the state of Oregon was admitted to the Union on February 14, 1859, and Oregon Territory was eliminated.

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

1845
Polk County created Polk created by the Provisional Legislature of Oregon Territory from Non-County Area 2; Non-County Area 2 eliminated. 22 December 1845 · Ore. Terr. Laws, general and local, 1843-1849, p. 38
1847
Lost territory Polk lost to creation of Benton. On 20 December 1847 the Journal of the Provisional Legislature recorded the passage of an act to redefine the boundaries of Polk. No such act appears within the session laws, but the definition of Benton depends on an earlier change having been made to the south line of Polk.
to Benton
23 December 1847 · Ore. Terr. Laws, general and local, 1843-1849, p. 50; Holman, 28-30; Oregon Archives, 237
1853
Lost territory Polk lost to creation of Tillamook.
to Tillamook
15 December 1853 · Ore. Terr. Special Laws, 1853, 5th reg. sess., p. 6
1859
Became part of Oregon Polk became an Oregon county when the state of Oregon was admitted to the Union and Oregon Territory was eliminated. 14 February 1859 · U.S. Stat., vol. 11, ch. 33[1859], secs. 1-2/pp. 383-384 Ore. Laws 1860, 1st reg. sess., pp. 28-30
1891
Exchanged territory Polk exchanged with Tillamook.
with Tillamook
21 February 1891 · Ore. Laws 1891, gen., 16th reg. sess., pp. 139-140

Show all 8 changes (3 more, mostly small adjustments)

1845
Polk County created Polk created by the Provisional Legislature of Oregon Territory from Non-County Area 2; Non-County Area 2 eliminated. 22 December 1845 · Ore. Terr. Laws, general and local, 1843-1849, p. 38
1847
Lost territory Polk lost to creation of Benton. On 20 December 1847 the Journal of the Provisional Legislature recorded the passage of an act to redefine the boundaries of Polk. No such act appears within the session laws, but the definition of Benton depends on an earlier change having been made to the south line of Polk.
to Benton
23 December 1847 · Ore. Terr. Laws, general and local, 1843-1849, p. 50; Holman, 28-30; Oregon Archives, 237
1853
Lost territory Polk lost to creation of Tillamook.
to Tillamook
15 December 1853 · Ore. Terr. Special Laws, 1853, 5th reg. sess., p. 6
1859
Became part of Oregon Polk became an Oregon county when the state of Oregon was admitted to the Union and Oregon Territory was eliminated. 14 February 1859 · U.S. Stat., vol. 11, ch. 33[1859], secs. 1-2/pp. 383-384 Ore. Laws 1860, 1st reg. sess., pp. 28-30
1891
Exchanged territory Polk exchanged with Tillamook.
with Tillamook
21 February 1891 · Ore. Laws 1891, gen., 16th reg. sess., pp. 139-140
1927
Lost territory Polk lost small corner to Lincoln.
to Lincoln
3 March 1927 · Ore. Laws 1927, gen., 34th reg. sess., ch. 278/pp. 350-351
1981
Boundary clarified Polk redefined to amend description in Oregon Revised Statutes (no change).
no change
13 July 1981 · Ore. Laws 1981, 61st reg. sess., ch. 332/p. 356
1983
Boundary clarified Polk boundary redefined to run along main channel of Willamette River as it was located on 22 June 1981 (no change).
no change
5 August 1983 · Ore. Laws 1983, 62nd reg. sess., ch. 780/pp. 1516-1517

Land and parcels

What the maps cover in Polk

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

Parcels Missing

No public parcel map found for Polk County yet. Lot lines and owners of record are kept by the county (co.polk.or.us).
Address points Official

One point per address, 40,185 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

Polk by the Census

Population

87,433 2020 Census count

Housing units

33,828 2020 Census count

Land area

741 square miles

Water area

3.2 square miles

People per sq mi

118 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 polkcountyor.gov

County government

County government
The official website of Polk County.
co.polk.or.us

See your own lot on these maps

Open Polk 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 Polk County

When was Polk County founded?: Polk County was founded in 1845, and named after James K. Polk.
What is the county seat of Polk County?: The county seat of Polk County is Dallas.
Is there an online parcel map for Polk County?: Not that we have found yet. Lot lines and owners of record are kept by the county assessor's office. When a public parcel map appears, it shows here.
Has Polk County's boundary or name changed?: Polk County was created in 1845. Since then the Atlas of Historical County Boundaries records 5 later changes, chiefly involving Tillamook County, Benton County and Lincoln County.
Who issues building permits in Polk 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 Polk County yet. Look up the address on FEMA's Flood Map Service Center, which shows the effective flood map for any lot.

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