Mount Hood is located along a convergent (subduction) plate boundary. It is part of the Cascade Volcanic Arc, a chain of volcanoes in the Pacific Northwest of the United States that formed as a result of the subduction of the Juan de Fuca Plate (an oceanic plate) beneath the North American Plate (a continental plate).
As the denser Juan de Fuca Plate sinks beneath the North American Plate at the Cascadia Subduction Zone, it descends into the mantle, where increasing heat and pressure cause water and other volatiles trapped in the subducting oceanic crust to be released. This process lowers the melting point of the overlying mantle rock, generating magma. The magma rises through the crust, and where it reaches the surface, it forms volcanoes—creating the Cascade Range, which stretches from northern California through Oregon and Washington into British Columbia, Canada.
Mount Hood, located in northern Oregon, is one of the prominent stratovolcanoes in this arc, along with others like Mount St. Helens, Mount Rainier, Mount Adams, and Mount Shasta. Stratovolcanoes are typically found at convergent boundaries and are characterized by steep, conical profiles built up from alternating layers of hardened lava, volcanic ash, and other eruptive materials.
Mount Hood is considered a potentially active volcano, with its most recent significant eruptive activity occurring in the 18th and 19th centuries. Its formation and ongoing volcanic potential are directly tied to the tectonic processes occurring at the Cascadia Subduction Zone, where the Juan de Fuca Plate continues to slide beneath the North American Plate at a rate of a few centimeters per year, sustaining the magma generation that fuels the Cascade volcanoes.