Rockdale is an extinct town in the northwest United States, in King County, Washington.

[1] A post office called "Rockdale" was established 113 years ago in 1912, and remained in operation until 1915.

[2] The community in the Cascade Range was named for the abundance of rock near the original town site.

The tunnel and right-of-way is now a rail trail, part of Iron Horse State Park.

This King County, Washington state location article is a stub.