County outline
Where Clackamas County is located
Area breakdown
Land accounts for 99.3% of Clackamas County’s measured area and water for 0.7%. Its combined area converts to 4,877 square kilometers or approximately 1,205,129 acres.
Green: land · blue: water
| Measurement | Square miles | Square kilometers | Acres |
|---|---|---|---|
| Land | 1,870.712 | 4,845.122 | 1,197,255.7 |
| Water | 12.302 | 31.862 | 7,873.3 |
| Total | 1,883.014 | 4,876.984 | 1,205,129 |
How Clackamas County compares
By original Census land area, Clackamas County ranks #18 of 36 in Oregon and #306 of 3,222 nationally. National rankings include the 50 states, District of Columbia, and Puerto Rico.
Its land area is 1.024 times the Oregon county-equivalent median of 1,826.2 square miles. It accounts for 1.9% of the combined county land area in the state.
See the complete Oregon ranking · What counts as a county equivalent?
Population and density of Clackamas County
The Census Bureau estimates that 426,280 people lived in Clackamas County on July 1, 2025. That ranks #181 of 3,222 county equivalents nationally and #3 of 36 in Oregon. Since the April 1, 2020 estimates base of 421,429, the population has grown by 4,851 (+1.2%), compared with +0.9% for Oregon as a whole.
With 1,870.7 square miles of land, that is 228 people per square mile (88 per km²), placing Clackamas County #600 nationally for density and #4 in Oregon. The median county equivalent has 47 people per square mile; the Oregon median is 25. Put another way, there are about 2.8 acres of land per resident.
| July 1 | 2020 | 2021 | 2022 | 2023 | 2024 | 2025 |
|---|---|---|---|---|---|---|
| Estimate | 422,483 | 423,877 | 423,098 | 424,076 | 425,245 | 426,280 |
| Change | — | +1,394 | −779 | +978 | +1,169 | +1,035 |
U.S. Census Bureau, Vintage 2025 population estimates. Estimates are revised each year and are not decennial census counts. Density divides the whole population by the whole county’s land area, so it describes an average, not how settlement is distributed within the county. Population sources and methods.
Cities and towns in Clackamas County
16 incorporated places lie at least partly in Clackamas County. Together they are home to 241,844 people (56.7%); the other 184,436 (43.3%) live outside any incorporated place, in unincorporated communities and rural areas.
The largest is Oregon City city, with 38,175 residents in the county. By land, Portland city is the largest at 133.5 mi² across all its counties. Among places with at least 1,000 residents in 2020, Estacada city grew fastest since then (+31.7%).
| Incorporated place | Population 2025 | Since 2020 | Land mi² |
|---|---|---|---|
| Oregon City cityCounty seat | 38,175 | +1.5% | 10.1 |
| Lake Oswego cityAlso in 2 other counties | 37,220 | −2.6% | 10.9 |
| Happy Valley city | 28,916 | +23.5% | 12 |
| West Linn city | 26,567 | −2.9% | 7.43 |
| Wilsonville cityAlso in 1 other county | 24,523 | −0.1% | 7.716 |
| Milwaukie cityAlso in 1 other county | 22,114 | +4.5% | 4.993 |
| Canby city | 18,004 | −0.9% | 4.773 |
| Sandy city | 13,323 | +5.4% | 3.692 |
| Gladstone city | 11,865 | −1.4% | 2.399 |
| Molalla city | 10,104 | −1.3% | 2.507 |
| Estacada city | 5,814 | +31.7% | 2.648 |
| Tualatin cityAlso in 1 other county | 3,192 | +1.3% | 8.418 |
| Portland cityAlso in 2 other counties | 850 | −0.5% | 133.5 |
| Johnson City city | 554 | +2.4% | 0.065 |
| Rivergrove cityAlso in 1 other county | 489 | −1.4% | 0.173 |
Show the other 1 places
| Name | Population 2025 | Since 2020 | Land mi² |
|---|---|---|---|
| Barlow city | 134 | +0.8% | 0.052 |
Population: U.S. Census Bureau Vintage 2025 subcounty estimates, counting only the part of each place inside Clackamas County. Land: 2026 Census Gazetteer, for the whole place even where it extends into other counties. How communities are listed.
Metropolitan area
Clackamas County is a central county of the Portland-Vancouver-Hillsboro, OR-WA Metropolitan Statistical Area. Its 7 county equivalents have 2,542,282 residents on 6,687.4 square miles of land; Clackamas County accounts for 28% of the land and 16.8% of the residents. By combined land it ranks #28 of 393 metropolitan areas, and #26 by population. It belongs to the Portland-Vancouver-Salem, OR-WA Combined Statistical Area.
| County equivalent | Population 2025 | Land mi² |
|---|---|---|
| Multnomah County | 795,391 | 431 |
| Washington County | 611,708 | 724.3 |
| Clark CountyWashington | 532,119 | 628.5 |
| Clackamas County | 426,280 | 1,870.7 |
| Yamhill County | 110,024 | 715.9 |
| Columbia County | 54,091 | 658.7 |
| Skamania CountyWashington | 12,669 | 1,658.3 |
ZIP codes
37 ZIP Code Tabulation Areas have land in Clackamas County; 24 of them have most of their land inside the county, and the others mainly cover neighboring areas.
97002970049700997011970139701597017970199702297023970279702897032970349703597038970429704597049970559706297067970689707097071970809708697089971329714097202972069721997222972679736297375
ZIP Code Tabulation Areas are the Census Bureau’s approximations of USPS ZIP Code service areas, from the 2020 Census relationship files. Lighter codes have less than half of their land in this county. Post-office-box and single-address ZIP Codes have no tabulation area.
Counties bordering Clackamas County
Clackamas County shares a land border with 6 county equivalents. It has more land than 5 of them. The largest neighbor is Wasco County (2,381.1 mi²) and the smallest is Multnomah County (431 mi²). Together with its neighbors, Clackamas County forms a block of 7,826.1 mi² of land, of which it holds 23.9%.
| Bordering county equivalent | Land mi² | Size vs. Clackamas | Compare |
|---|---|---|---|
| Wasco County | 2,381.1 | 1.3× larger | Compare |
| Marion County | 1,180.8 | 1.6× smaller | Compare |
| Washington County | 724.3 | 2.6× smaller | Compare |
| Yamhill County | 715.9 | 2.6× smaller | Compare |
| Hood River County | 522.2 | 3.6× smaller | Compare |
| Multnomah County | 431 | 4.3× smaller | Compare |
How big is Clackamas County compared with U.S. states?
Clackamas County has more land than 1 of the 50 states. It is about 1.8 times the land area of Rhode Island (1,033.9 mi²), while Delaware, the next larger state, has 1 times as much land (1,948.6 mi²). Oregon’s county land could hold about 51 areas the size of Clackamas County.
Another way to picture it: the same land area would fill a square about 43.3 miles (69.6 km) on each side. Real county shapes are rarely square, so this is a scale reference rather than a width or driving distance.
State figures are the sums of each state’s county-equivalent land measurements in the same Census release, so states and counties are compared on the same basis. Published state totals can differ slightly because of rounding. Compare all states · Counties bigger than entire states.
What stands out about Clackamas County?
Clackamas County has more land than 2,916 of the other 3,221 county equivalents in the dataset.
A median is the middle county-equivalent measurement, not the average of the largest and smallest. All three bars use the same linear scale. Very small areas may appear as a thin sliver; the labels retain their values.
Does including water change its rank?
Using land plus water places Clackamas County at #348 nationally by total area, 42 places farther from the top than its land rank. Other county equivalents gain more area when their water measurements are included.
Its water share is 0.7%, compared with a national county-equivalent median of 1.2% — 0.5 percentage points lower. This describes the statistical geography’s land/water mix, not flood exposure or developable land.
Closest positions in the national land ranking
These entries sit immediately beside Clackamas County in the national ranking. They can be in different states and are not necessarily geographic neighbors.
| Land rank | County equivalent | Land mi² | Comparison |
|---|---|---|---|
| #305 | Klickitat County, Washington | 1,871.6 | Compare |
| #306 | Clackamas County, Oregon | 1,870.7 | This county |
| #307 | Summit County, Utah | 1,870.7 | Compare |
Calculated from the same Census release as the area table. Total-area order uses original ALAND + AWATER; water shares and chart labels use published square miles. Calculation details.
Representative coordinates
The Census internal point is 45.160493, -122.195127. It represents a location inside the geography; it is not necessarily the centroid or the address of a courthouse.
Source and precision
U.S. Census Bureau, 2026 Gazetteer Files, Counties. Original ALAND: 4,845,121,430 m²; AWATER: 31,861,093 m². Rankings use ALAND; exact ties use ascending GEOID. Tables preserve Census-published square miles to three decimals, with conversions based on those values.
Common questions
How big is Clackamas County?
Clackamas County, Oregon has 1,870.7 square miles (4,845.1 km²) of land and 12.3 square miles of water, for a total area of 1,883 square miles. It ranks #306 of 3,222 U.S. county equivalents by land area.
Is Clackamas County the largest county in Oregon?
No. Clackamas County ranks #18 of 36 in Oregon by land area. The largest is Harney County, with 10,134.5 square miles of land.
What counties border Clackamas County?
Clackamas County shares a land border with Marion County, Multnomah County, Wasco County, Hood River County, Washington County, and Yamhill County.
What is the population of Clackamas County?
The Census Bureau estimates Clackamas County had 426,280 residents on July 1, 2025, ranking #181 of 3,222 county equivalents. That is 228 people per square mile of land.
What is the county seat of Clackamas County?
The county seat of Clackamas County is Oregon City.
What cities and towns are in Clackamas County?
Clackamas County has 16 incorporated places. The most populous five are Oregon City city, Lake Oswego city, Happy Valley city, West Linn city, and Wilsonville city; 184,436 residents live outside any incorporated place.
Is Clackamas County part of a metropolitan area?
Yes. It is a central county of the Portland-Vancouver-Hillsboro, OR-WA Metropolitan Statistical Area, which has 7 county equivalents and 2,542,282 residents.
How many ZIP codes are in Clackamas County?
37 ZIP Code Tabulation Areas have land in Clackamas County, and 24 of them have most of their land inside the county. Census ZIP Code Tabulation Areas approximate USPS ZIP Code areas.
How does Clackamas County compare with U.S. states?
It has more land than 1 of the 50 states, including Rhode Island (1,033.9 square miles of land).
How many acres of land are in Clackamas County?
The land measurement converts to approximately 1,197,256 acres. Including water, total area is approximately 1,205,129 acres. One square mile equals 640 acres.
Why might another source show a different area?
Check whether it reports land or total area, its Census vintage, and its rounding. Our guide explains how to reconcile county area figures.
Can this establish a property boundary?
No. Statistical measurements and generalized maps do not establish property lines. Consult the relevant local surveying or land-records authority.