Here is more info and a link about the King County Elections center:
The King County Elections office offers a wonderful viewing loop for the public to take a self-guided tour without an appointment to observe the election process in action. The viewing loop is open during business hours: week days 8:30 a.m. to 4:30 p.m., with extended hours on Election Days. We recommend visiting during an election, which usually take place in August, November, February and April. For more information call 206-296-VOTE (8683).
Download the Tour Map
Directions to King County Elections