Directions to Washington County Administration Directions to Washington County Administration Search | Advanced Search | New Members | Coupons and Discounts | All Categories Government & Education >> GOVERNMENT AGENCIES Washington County Administration 155 N 1st Ave, #300, MS-21Hillsboro, OR 97124 | map (503) 846-8685 | fax: (503) 846-4545 Visit Site Get directions to: Washington County Administration, 155 N 1st Ave, #300, MS-21, Hillsboro OR Get directions from: Click to Print This Page If your business isn't here, contact us today to get listed!