Hillsboro, city, seat of Washington County, northwestern Oregon, in the Tualatin Valley; incorporated 1876. A suburb of Portland situated in an agricultural and lumbering region, it has some high-technology industrial activity. The Jackson Bottom Wetland Preserve borders the city. Settled in 1841, the community was laid out in 1842 by David Hill, for whom it was named after being called Columbia for a time. Population 27,664 (1980); 37,520 (1990); 70,186 (2000).
