Ahtanum Ridge is a long

anticline In structural geology, an anticline is a type of Fold (geology), fold that is an arch-like shape and has its oldest Bed (geology), beds at its core, whereas a syncline is the inverse of an anticline. A typical anticline is convex curve, c ...

mountain A mountain is an elevated portion of the Earth's crust, generally with steep sides that show significant exposed bedrock. Although definitions vary, a mountain may differ from a plateau in having a limited summit area, and is usually higher t ...

ridge A ridge is a long, narrow, elevated geomorphologic landform, structural feature, or a combination of both separated from the surrounding terrain by steep sides. The sides of a ridge slope away from a narrow top, the crest or ridgecrest, wi ...

Yakima County Yakima County is a County (United States), county in the U.S. state of Washington (state), Washington. As of the 2020 United States census, 2020 census, its population was 256,728. The county seat and most populous city is Yakima, Washington, Ya ...

in the

U.S. state In the United States, a state is a constituent political entity, of which there are 50. Bound together in a political union, each state holds governmental jurisdiction over a separate and defined geographic territory where it shares its so ...

Washington Washington most commonly refers to: * George Washington (1732–1799), the first president of the United States * Washington (state), a state in the Pacific Northwest of the United States * Washington, D.C., the capital of the United States ** A ...

. It is located just south of the city of

Yakima Yakima ( or ) is a city in and the county seat of Yakima County, Washington, United States, and the state's 11th most populous city. As of the 2020 census, the city had a total population of 96,968 and a metropolitan population of 256,728. The ...

, and much of its length is at the northern edge of the

Yakama Indian Reservation The Yakama Indian Reservation (spelled Yakima until 1994) is a Native American reservation in Washington state of the federally recognized tribe known as the Confederated Tribes and Bands of the Yakama Nation. The tribe is made up of Klikitat ...

. Its name comes from the

Sahaptin The Sahaptin are a number of Native American tribes who speak dialects of the Sahaptin language. The Sahaptin tribes inhabited territory along the Columbia River and its tributaries in the Pacific Northwest region of the United States. Sahaptin- ...

toponym �tanɨm Ahtanum Ridge is part of the

Yakima Fold Belt The Yakima Fold Belt of south-central Washington, also called the Yakima fold-and-thrust belt, is an area of topographical folds (or wrinkles) raised by tectonic compression. It is a structural-tectonic sub province of the western Columbia Plat ...

of east-tending long ridges formed by the folding of

Miocene The Miocene ( ) is the first epoch (geology), geological epoch of the Neogene Period and extends from about (Ma). The Miocene was named by Scottish geologist Charles Lyell; the name comes from the Greek words (', "less") and (', "new") and mea ...

Columbia River basalt flows.Complete Report for Saddle Mountains structures
, USGS Earthquake Hazards Program Ahtanum Ridge separates Yakima Valley on the south from

Ahtanum Valley There are two things named Ahtanum in the U.S. state of Washington: *Ahtanum, Washington Ahtanum () is a census-designated place (CDP) in Yakima County, Washington. The population was 4,046 at the time of the 2020 census. Geography According to ...

on the north. At the eastern end of Ahtanum Ridge the

Yakima River The Yakima River is a tributary of the Columbia River in south central and eastern Washington state, named for the indigenous Yakama people. Lewis and Clark mention in their journals that the Chin-nâm pam (or the Lower Snake River Chamnapam N ...

flows through Union Gap. The ridge continues east of

Union Gap Union Gap is a city in Yakima County, Washington, United States. The population was 6,568 at the 2020 census. Union Gap has become the retail hub for the entire Yakima Valley as a result of Valley Mall and other thriving businesses being locat ...

as the

Rattlesnake Hills The Rattlesnake Hills, also known as Rattlesnake Ridge, is a 16-mile (26 km) long anticline mountain ridge in Yakima County, Washington, Yakima County and Benton County, Washington, Benton County in the U.S. state of Washington (state), Wash ...

References

External links

* Ridges of Washington (state) Ridges of Yakima County, Washington Washington (state) placenames of Native American origin {{YakimaCountyWA-geo-stub