When was Clackamas County founded?

Clackamas County was founded in 1843, and named after Clackamas people.

What is the county seat of Clackamas County?

The county seat of Clackamas County is Oregon City.

Is there an online parcel map for Clackamas County?

Yes. A public source publishes a parcel map of 163,927 parcels, rated good enough here. You can click any parcel on it in Parcel Chart's free map, no sign-in needed.

Has Clackamas County's boundary or name changed?

Clackamas County was created in 1843. Since then the Atlas of Historical County Boundaries records 13 later changes, chiefly involving Washington County, Marion County and Multnomah County. It was formerly called Clackamas District.

Who issues building permits in Clackamas County?

The county's page on building permits: New Single-Family Residence Permit Fee Estimator. Inside a city or town, ask that city first.

Who issues septic and well permits in Clackamas County?

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

Is my lot in a flood zone?

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

County · code 41005

Clackamas CountyOregon

Clackamas County is a county in Oregon with its seat at Oregon City. It was created in 1843 as one of four original Oregon counties and named after the Clackamas people.

Founded1843
County seatOregon City
Named forClackamas people
Land area1,871 sq mi + 12 sq mi water
Population421,401 2020 Census
Parcels mapped163,927 checked 15 October 2026

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

Updated 20 October 2026

Census outline · seat marked

History

Founded in 1843

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

Clackamas County was created on July 5, 1843, as one of four original Oregon counties and initially included parts of present Oregon, Washington, Idaho, Montana, and Canada. In 1844, its boundaries were redefined to run along the Columbia River, and in 1845 it gained territory from Champoeg District (now Marion County) before being renamed from Clackamas District to Clackamas County. When Oregon became a state in 1859, Clackamas County became an Oregon county after Oregon Territory was eliminated.

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

1843
Clackamas County created Clackamas District (now Clackamas) created. Clackamas was one of four original counties created by the Provisional Legislature of Oregon Territory. Included parts of present Oregon, Washington, Idaho, Montana and Canada. 5 July 1843 · Oregon Archives, p. 26
1844
Lost territory Clackamas District (now Clackamas) lost to creation of Non-County Area 1 when the Clackmas boundary was redefined to run along the Columbia River.
to Clackmas
27 June 1844 · Ore. Terr. Laws, general and local, 1843-1849, p. 74
1845
Renamed Clackamas District (Oregon) renamed Clackamas County; no change in boundaries.
formerly Clackamas District
22 December 1845 · Ore. Terr. Laws, general and local, 1843-1849, p. 35
1853
Clackamas County created Part of Clackamas (Oregon) became Non-County Area 1 when the United States created Washington Territory from Oregon Territory. Remainder of Clackamas (Oregon) eliminated from Washington Territory. 2 March 1853 · Wash. Terr. Laws, 1854, 1st. sess., p. 32; Van Zandt, 155
1859
Became part of Oregon Clackamas 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

Show all 15 changes (10 more)

1843
Clackamas County created Clackamas District (now Clackamas) created. Clackamas was one of four original counties created by the Provisional Legislature of Oregon Territory. Included parts of present Oregon, Washington, Idaho, Montana and Canada. 5 July 1843 · Oregon Archives, p. 26
1844
Lost territory Clackamas District (now Clackamas) lost to creation of Non-County Area 1 when the Clackmas boundary was redefined to run along the Columbia River.
to Clackmas
27 June 1844 · Ore. Terr. Laws, general and local, 1843-1849, p. 74
1845
Gained territory Clackamas District (now Clackamas) gained from Champoeg District (now Marion). Boundary between Clackamas District and Tuality District (now Washington) redefined to run "along the middle of the main channel of the Willamette River to the center of the Columbia River at the upper mouth of the Willamette."
from Champoeg District from Marionfrom Tuality Districtfrom Washington
19 December 1845 · Ore. Terr. Laws, general and local, 1843-1849, pp. 36-37
1845
Renamed Clackamas District (Oregon) renamed Clackamas County; no change in boundaries.
formerly Clackamas District
22 December 1845 · Ore. Terr. Laws, general and local, 1843-1849, p. 35
1846
Lost territory Clackamas lost to British North America when the Oregon Boundary Treaty between the United States and Great Britain established the northern boundary of Oregon Territory at 49 degrees north latitude. 15 June 1846 · Hayes, 134, 171-174; Parry 100:40-42; Van Zandt, 18
1853
Clackamas County created Part of Clackamas (Oregon) became Non-County Area 1 when the United States created Washington Territory from Oregon Territory. Remainder of Clackamas (Oregon) eliminated from Washington Territory. 2 March 1853 · Wash. Terr. Laws, 1854, 1st. sess., p. 32; Van Zandt, 155
1854
Lost territory Clackamas lost to creation of Wasco.
to Wasco
11 January 1854 · Ore. Terr. Special Laws 1853, 5th reg. sess., pp. 26-27
1854
Gained territory Clackamas gained from Washington and Yamhill; lost to creation of Multnomah.
from Washington from Yamhill from Multnomah
22 December 1854 · Ore. Terr. Special Laws 1854, 6th reg. sess., p. 29
1856
Gained territory Clackamas gained from Marion.
from Marion
30 January 1856 · Ore. Terr. Laws 1855-1856, 7th reg. sess., p. 50
1859
Became part of Oregon Clackamas 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
1860
Gained territory Clackamas gained from Yamhill.
from Yamhill
17 October 1860 · Ore. Laws 1860, 1st reg. sess., p. 47
1862
Gained territory Clackamas gained from Washington.
from Washington
17 October 1862 · Ore. Laws 1862, 2nd reg. sess., p. 98
1893
Lost territory Clackamas lost small area (part of the town of Sellwood) to Multnomah.
to Multnomah
20 February 1893 · Ore. Laws 1893, gen., 17th reg. sess., pp. 78-79
1893
Exchanged territory Clackamas exchanged with Washington.
with Washington
22 February 1893 · Ore. Laws 1893, gen., 17th reg. sess., pp. 161-162
1911
Boundary clarified Clackamas boundary with Marion redefined (no change).
with Marionno change
8 February 1911 · Ore. Laws 1911, gen., 26th reg. sess., ch. 22/p. 39

Land and parcels

What the maps cover in Clackamas

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

Parcels Good enough

Lot lines and tax-map numbers for 163,927 parcels. Drawn for tax purposes: usually within a few feet of a survey, but not a survey.
edited 14 October 2026 · checked 15 October 2026
Address points Official

One point per address, 185,577 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

Clackamas by the Census

Population

421,401 2020 Census count

Housing units

170,094 2020 Census count

Land area

1,871 square miles

Water area

12 square miles

People per sq mi

225 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

Clerk of court: deeds and platsfrom clackamas.us · checked 13 October 2026

Permits

Health department: septic and well 503-742-4740from clackamas.us · checked 13 October 2026
New Single-Family Residence Permit Fee Estimatorfrom apps.clackamas.us
Septic Program Fee Schedulefrom dochub.clackamas.us
septic documents and guidance pagefrom clackamas.us

Zoning and code

Planning and zoning 503-742-4240from clackamas.us · checked 13 October 2026
Proposed Ordinance Amendmentsfrom clackamas.us
Planning and Zoningfrom clackamas.us
Zoning and Development Ordinancefrom clackamas.us

County government

County government
The official website of Clackamas County.
clackamas.us

See your own lot on these maps

Open Clackamas 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 Clackamas County

When was Clackamas County founded?: Clackamas County was founded in 1843, and named after Clackamas people.
What is the county seat of Clackamas County?: The county seat of Clackamas County is Oregon City.
Is there an online parcel map for Clackamas County?: Yes. A public source publishes a parcel map of 163,927 parcels, rated good enough here. You can click any parcel on it in Parcel Chart's free map, no sign-in needed.
Has Clackamas County's boundary or name changed?: Clackamas County was created in 1843. Since then the Atlas of Historical County Boundaries records 13 later changes, chiefly involving Washington County, Marion County and Multnomah County. It was formerly called Clackamas District.
Who issues building permits in Clackamas County?: The county's page on building permits: New Single-Family Residence Permit Fee Estimator. Inside a city or town, ask that city first.
Who issues septic and well permits in Clackamas County?: The county's page on septic systems and wells: Health department: septic and well.
Is my lot in a flood zone?: We do not have flood maps for Clackamas County yet. Look up the address on FEMA's Flood Map Service Center, which shows the effective flood map for any lot.

Nearby