2009 Journal of Volcanology and Geothermal Research paper:
Plume buoyancy (magma) y has produced a ~ 400-km-wide (248 miles) , ~ 500-m- (1017.06 feet) high topographic swell centered on the Yellowstone Plateau That's one hell of a big volcano. But all they talk about is the center, caldera. http://marygreeley.com/?p=63382