Washington County, Oregon GOVERNMENT AGENCIES Washington County, Oregon GOVERNMENT AGENCIES Search | Advanced Search | New Members | Coupons and Discounts | All Categories Sort alphabetically by... Name City Washington County Administration _ 155 N 1st Ave, #300, MS-21Hillsboro, OR 97124 (503) 846-8685 Learn More | Visit Site | Show on Map City of Hillsboro _ 150 East Main St.Hillsboro, OR 97123 (503) 681-6100 Learn More | Visit Site | Show on Map If your business isn't here, contact us today to get listed!