The cave at Oregon Caves National Monument and Preserve is a solution cave formed in a marble outcrop located in Siskiyou mountain range of Southwest Oregon.
The marble formed as a consequence of tectonic activity. Limestone of the Juan de Fuca oceanic plate subducted under the North American continental plate and was metamorphosed (recrystallized) into marble. The intense faulting and folding incurred by the marble resulted in a geosynclinic karst system. The predominant rectilinear branchwork passages are a result of the steep upper profile of the bedding planes.
The surrounding forest, watershed, and temperature - and human history - all have an influence on the cave.