Seattle-Tacoma area

In the real world, Seattle and Tacoma are two major cities in Washington State, comprising the financial and military hub of the region.

Fiction

Generation 1

Animated continuity

When Megatron brought the Key to Vector Sigma to Earth, he began experimenting with it in an area identified by Teletraan-1 as "40 miles west of the Seattle-Tacoma area." That would be the Olympic National Park, which is consistent with the evergreen forest Megatron began cyberforming with the Key. The ensuing battle threatened a nearby city, though it's unlikely it was either Seattle or Tacoma, based on geography and proximity.

The Key to Vector Sigma, Part 2

From Teletraan I: The Transformers Wiki, a Wikia wiki.