Clackamas County Government in the Portland Metro Area
Clackamas County is one of three counties — alongside Multnomah and Washington — that anchor the Portland metro area's governmental structure. As Oregon's third-most populous county, it operates a distinct elected board-governed framework that intersects with regional bodies, municipal governments, and state agencies in ways that directly affect land use, public health, transportation, and social services for roughly 430,000 residents (U.S. Census Bureau, 2020 Decennial Census). This page explains how Clackamas County government is structured, how it functions alongside Portland's city and regional institutions, and where its authority begins and ends.
Definition and scope
Clackamas County government is a general-purpose county government established under Oregon's constitutional framework for counties, which grants counties both general administrative authority and specific statutory mandates in areas such as elections, property assessment, public health, and land use planning (Oregon Revised Statutes Chapter 203). The county operates under a Board of County Commissioners consisting of 5 elected members who serve staggered 4-year terms.
The county's geographic scope covers approximately 1,879 square miles, making it the largest of the three Portland-area counties by land area. That footprint includes fully urban incorporated cities such as Lake Oswego and Oregon City, suburban communities like West Linn and Tualatin, and large rural and forestland zones in the Mount Hood corridor.
What falls within Clackamas County's authority:
- Unincorporated land use planning and zoning
- Property tax assessment and collection
- County Sheriff and adult corrections
- Public health programs and mental health services
- County road maintenance (distinct from ODOT state highways)
- Elections administration for all Clackamas County voters, including those residing in incorporated cities
- Social services, including Oregon Department of Human Services programs administered at the county level
What is not covered by Clackamas County government: Municipalities within the county — Oregon City, Lake Oswego, Milwaukie, Happy Valley, and others — maintain independent city charters and govern their own police, zoning, utilities, and municipal services. Clackamas County government does not govern Portland; the City of Portland lies primarily within Multnomah County. State highway maintenance, including Highway 26 (Mount Hood Corridor), falls under the Oregon Department of Transportation, not the county.
For a broader orientation to how Clackamas County fits within the multi-jurisdictional Portland metro structure, the Portland Metro Authority index organizes reference coverage across the region's overlapping governmental layers.
How it works
The Board of County Commissioners functions as both the legislative and executive body for Clackamas County. Unlike Oregon's most populous county, Multnomah, which operates under a charter with a separate county chair and executive structure, Clackamas County uses a commission model in which the 5 elected commissioners collectively set policy and administer county operations through appointed department directors.
Key functional divisions include:
- Assessment and Taxation — Assesses all real and personal property within county boundaries and certifies tax rolls transmitted to the Oregon Department of Revenue for rate calculation.
- County Counsel — Provides legal representation for the board and county departments; distinct from municipal city attorneys.
- Public Health — Administers state-delegated public health programs under ORS Chapter 431, including communicable disease response, environmental health inspections, and behavioral health services.
- Community Development — Manages land use planning in unincorporated areas in compliance with Oregon's statewide planning goals, administered by the Oregon Department of Land Conservation and Development (DLCD).
- County Sheriff — Provides law enforcement in unincorporated areas and operates the county jail under elected sheriff authority independent of the board.
- Clackamas County Roads — Maintains approximately 1,300 miles of county-maintained roads separate from ODOT and municipal street systems.
The county also participates in Metro, the directly elected regional government that exercises planning authority over the Urban Growth Boundary (UGB) across all three Portland-area counties. Clackamas County cannot unilaterally expand the UGB; that authority rests with Metro. For more on how the UGB operates, see the Portland Urban Growth Boundary reference page.
Budgetarily, Clackamas County adopts an annual budget through a citizen Budget Committee — composed of the 5 commissioners plus 5 appointed citizens — as required under Oregon Local Budget Law (ORS Chapter 294).
Common scenarios
Property tax questions: Clackamas County residents with questions about assessed value, exemptions (such as the senior deferral program), or tax payment status contact the Clackamas County Assessment and Taxation office, not the Oregon Department of Revenue directly. The county issues annual assessment notices and manages the appeal process through the county Board of Property Tax Appeals.
Land use permits in unincorporated areas: A property owner in an unincorporated part of Clackamas County — for example, rural land near Sandy or Damascus — applies for building permits and land use approvals through Clackamas County Community Development, not through any city planning department. Properties inside incorporated cities apply to those cities' planning departments instead.
Elections administration: All voters registered in Clackamas County — whether in Oregon City, Lake Oswego, or unincorporated rural areas — cast ballots administered by the Clackamas County Elections office under Oregon's vote-by-mail system. The county also administers Metro, TriMet, and school district elections for its geographic portion of those districts.
Social services access: Programs including SNAP (food benefits), Oregon Health Plan enrollment, and child welfare services are delivered through county-level offices. In Clackamas County, these are co-administered with the Oregon Department of Human Services through offices in Oregon City and Clackamas.
Sheriff vs. city police: In Clackamas County's unincorporated areas — which account for a substantial share of the county's land — the Clackamas County Sheriff's Office provides primary law enforcement. Incorporated cities such as Milwaukie maintain their own police departments. Understanding this distinction is essential when determining which agency has jurisdiction over a specific address.
Decision boundaries
Clackamas County government's authority intersects with at least 4 distinct governmental layers in the Portland metro:
| Governmental body | Primary role in Clackamas County context |
|---|---|
| Clackamas County | Unincorporated land use, elections, sheriff, property tax, public health |
| Metro (Regional Government) | Urban Growth Boundary, regional transportation planning, waste management |
| Incorporated municipalities | City-specific zoning, police, parks, utilities within city limits |
| Oregon State agencies | State highways, statewide land use goals, public university system, state courts |
A key distinction exists between Clackamas County and its neighbor Multnomah County: Multnomah County contains Portland proper and operates under a Home Rule charter that provides broader self-governing authority than Clackamas County's statutory commission structure. Similarly, Washington County on the west side operates a commission structure but differs in its urban development patterns and participation in the Westside MAX light rail corridor via TriMet.
Clackamas County's relationship with Metro creates a binding planning constraint: any expansion of urban services into unincorporated county land requires Metro approval for UGB amendments before the county can authorize urban-density zoning. This two-step jurisdictional boundary is a frequent point of confusion in development proposals along the county's urban fringe, including areas near Damascus and the Sunrise Corridor.
Scope limitations: This page addresses county-level governmental structure. It does not cover individual city governments within Clackamas County, the Clackamas Community College District, school district governance, or the Mount Hood National Forest (a federal entity administered by the U.S. Forest Service). Regional coordination functions — including the Joint Office of Homeless Services — involve Clackamas County as a participant but are governed through separate intergovernmental agreements.
References
- Clackamas County Government — Official Site
- Oregon Revised Statutes Chapter 203 — County Governing Bodies
- Oregon Revised Statutes Chapter 294 — Local Budget Law
- Oregon Revised Statutes Chapter 431 — Public Health
- Oregon Department of Land Conservation and Development (DLCD)
- Metro Regional Government — Urban Growth Boundary
- Oregon Secretary of State — Voting in Oregon
- Oregon Department of Human Services
- U.S. Census Bureau — 2020 Decennial Census
- U.S. Forest Service — Mount Hood National Forest