Rockdale is an extinct town in the

northwest The points of the compass are a set of horizontal, radially arrayed compass directions (or azimuths) used in navigation and cartography. A compass rose is primarily composed of four cardinal directions—north, east, south, and west—each sep ...

United States The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country primarily located in North America. It consists of 50 states, a federal district, five major unincorporated territorie ...

, in

King County King County is located in the U.S. state of Washington. The population was 2,269,675 in the 2020 census, making it the most populous county in Washington, and the 13th-most populous in the United States. The county seat is Seattle, also the st ...

Washington Washington commonly refers to: * Washington (state), United States * Washington, D.C., the capital of the United States ** A metonym for the federal government of the United States ** Washington metropolitan area, the metropolitan area centered on ...

. The GNIS classifies it as a populated place. A post office called "Rockdale" was established in 1912, and remained in operation until 1915. The community in the

Cascade Range The Cascade Range or Cascades is a major mountain range of western North America, extending from southern British Columbia through Washington and Oregon to Northern California. It includes both non-volcanic mountains, such as the North Cascades, ...

was named for the abundance of rock near the original town site. Just south of

Snoqualmie Pass Snoqualmie Pass is a mountain pass that carries Interstate 90 (I-90) through the Cascade Range in the U.S. state of Washington. The pass summit is at an elevation of , on the county line between Kittitas County and King County. Snoqualmie Pass ...

, it was at the west portal of the

Snoqualmie Tunnel The Snoqualmie Tunnel is a former railroad tunnel near Snoqualmie Pass in the U.S. state of Washington, located east of Seattle. The tunnel crosses the Cascade Range about south of the pass, which is used by Interstate 90, on the border betwee ...

, constructed by the

Chicago, Milwaukee, St. Paul and Pacific Railroad The Chicago, Milwaukee, St. Paul and Pacific Railroad (CMStP&P), often referred to as the "Milwaukee Road" , was a Class I railroad that operated in the Midwest and Northwest of the United States from 1847 until 1986. The company experience ...

(The Milwaukee Road) from 1912 to 1914. The

elevation The elevation of a geographic location is its height above or below a fixed reference point, most commonly a reference geoid, a mathematical model of the Earth's sea level as an equipotential gravitational surface (see Geodetic datum § Vert ...

is approximately above

sea level Mean sea level (MSL, often shortened to sea level) is an average surface level of one or more among Earth's coastal bodies of water from which heights such as elevation may be measured. The global MSL is a type of vertical datuma standardised g ...

; it is south of and about above the eastbound lanes of

Interstate 90 Interstate 90 (I-90) is an east–west transcontinental freeway and the longest Interstate Highway in the United States at . It begins in Seattle, Washington, and travels through the Pacific Northwest, Mountain West, Great Plains, Midwest, and ...

, formerly U.S. Route 10. The tunnel and

right-of-way Right of way is the legal right, established by grant from a landowner or long usage (i.e. by prescription), to pass along a specific route through property belonging to another. A similar ''right of access'' also exists on land held by a gov ...

is now a

rail trail A rail trail is a shared-use path on railway right of way. Rail trails are typically constructed after a railway has been abandoned and the track has been removed, but may also share the right of way with active railways, light rail, or streetcar ...

, part of

Iron Horse State Park Iron Horse State Park, part of the Washington State Park System, is a state park located in the Cascade Mountains and Yakima River Valley, between Cedar Falls on the west and the Columbia River on the east. The park is contiguous with a ...

References

47.392,-121.455 Ghost towns in Washington (state) Geography of King County, Washington {{KingCountyWA-geo-stub