A hotspot is a volcanic region fed by narrow streams of hot mantle rising from the Earth's core-mantle boundary known as a mantle plume. Hotspots may be on, near or far from tectonic plate boundaries. As tectonics plates move over the surface of the Earth, the hotspot remains in place. This causes line of volcanism to extend over many miles across the surface of the Earth. The Hawaiian Islands and Yellowstone National Park were both formed by hot spots.