Rocky Butte is an extinct cinder cone butte in Portland, Oregon, United States. It is also part of the Boring Lava Field, a group of volcanic vents and lava flows throughout Oregon and Washington state. The volcano erupted between 285,000 and 500,000 years ago.
As part of the Boring Lava Field, Rocky Butte is considered an outlier of the Cascade Range. It was also produced by the subduction of the oceanic Juan de Fuca tectonic plate under the North American tectonic plate; it is the core remnant of intrusive rock from a late Pleistocene volcano. The Butte has a calc-alkaline composition and consists of basaltic andesite with olivine phenocrysts.
Address 3203 NE Rocky Butte Rd, Portland 97220, United States
Coordinates 45°32'47.697" N -122°33'57.345" E