This category includes Cascade volcanoes, i.e. volcanoes which are formed by subduction along the Cascadia subduction zone (members of the Cascade Volcanic Arc). This is a geological category, not a geographical one. The volcanoes in this category are found in California, Oregon, Washington, and British Columbia, and in two different mountain ranges, the Cascade Range and the Coast Mountains. The Cascade volcanoes are part of the Pacific Ring of Fire that includes over 160 active volcanoes.
Articles listed under this category should be cross-listed under the correct geographical categories too. For mountain range categories, the appropriate choices are Category:Cascade Range or Category:Pacific Ranges. For state/province, use the appropriate "Volcanoes of" category, e.g. Category:Volcanoes of California.