Washington County, Oregon Events Event(s) for Saturday, October 31, 2015 Date Event Category 10/31/2015 Downtown Hillsboro's Annual Safe 'n Sane Halloween Celebration Community 10/31/2015 Halloween in Orenco! Community The indicates on-line registration is available for this event. Enter your email address and "check" the box for each event that interests you. You will automatically receive an email reminder before the event! Your Email Address Remind me 1 2 3 4 5 day(s) prior to the event date.