Washington State is not all that well-known for producing large gold nuggets. In fact, compared to nearly all of the western states in the U.S. it is probably the poorest state to try and find large gold nuggets (although there are plenty of places where smaller placer gold is commonly found.)
However, there is one place in Washington that has a history of producing some spectacular gold nuggets over the years, and that is in the mining town of Liberty.
Located north of Ellensburg, the richest gold bearing areas around Liberty were found in Swauk and Williams Creeks. The earliest discoveries here were made back in 1873, and unlike most other areas that only produced fine gold dust and flakes, large nuggets were readily found in the Swauk district.