Buying Land in Washington County, Oregon

Inside the UGB: the most urbanized county in this batch

Washington County is unlike the other counties in this Oregon batch in one fundamental respect: most of it sits inside the Portland-area Metro urban growth boundary, covering Beaverton, Cornelius, Durham, Forest Grove, Hillsboro, King City, Sherwood, Tigard, and parts of Lake Oswego, Portland, Rivergrove, Tualatin, and Wilsonville. Land inside that boundary is urbanizable, planned for eventual development under city and county comprehensive plans; land outside it -- even land immediately adjacent to a city -- is treated as rural or resource land under the same statewide Goal 3/Goal 4 rules that apply anywhere else in Oregon. For a buyer, confirming exactly which side of the UGB a parcel sits on, using Metro's own boundary lookup tool, is a more consequential first step here than in almost any other Oregon county, since the practical difference between the two sides is enormous.

A live 2023-2024 fight over semiconductor land and the UGB

Washington County was at the center of a genuine, dated statewide land-use episode in 2023-2024. Oregon's Senate Bill 4 gave the governor a time-limited power -- through the end of 2024 -- to designate specific sites for large-scale semiconductor and industrial development outside the normal, multi-year UGB expansion process, in direct response to national competition for chip-manufacturing investment. Governor Kotek used that authority to advance a 373-acre site adjacent to Hillsboro. At the same time, a competing 430-acre site favored by some local officials near Cornelius ran into a genuine legal obstacle: the land had been designated a "rural reserve" under the region's urban/rural reserves framework, meaning it was explicitly set aside as off-limits to development for the long term -- not simply undesignated rural land available for a UGB amendment. North Plains, separately, had its own pending request to the Department of Land Conservation and Development to expand its UGB for a similar purpose.

This episode is covered in full on our dedicated zoning page for Washington County, including how the rural-reserve designation differs from ordinary rural EFU or forest zoning and what that distinction means if you're evaluating land anywhere near one of these sites. The short version for a land buyer: proximity to Hillsboro's semiconductor cluster does not automatically mean a nearby rural parcel is a plausible future UGB-expansion candidate -- some of the most obviously convenient sites were specifically walled off from that possibility years in advance.

The rural west side: Gaston, Timber, and ordinary EFU/forest rules

West of the urbanized core, Washington County still has a genuinely rural character around communities like Gaston and Timber, and near the former Wapato Lake area. That land is governed by the county's Rural/Natural Resource Plan and falls under the same Exclusive Farm Use and forest-zone rules that apply in any rural Oregon county -- a confirmed EFU zone exists in the county's own code, administered by the Long Range Planning division alongside the Community Development Code that governs the urbanized areas. A buyer evaluating rural west-county land should treat it like rural land anywhere else in Oregon -- subject to standard EFU dwelling-eligibility tests -- rather than assuming Washington County's urban, semiconductor-driven reputation extends to every parcel in the county.