There is no universally accepted definition of what a mountain is. For whatever it's worth, Wikipedia says things like "official UK government's definition of a mountain, for the purposes of access, is a summit of 600 metres or higher", and "At one time the U.S. Board on Geographic Names defined a mountain as being 1,000 feet (300 m) or taller, but has abandoned the definition since the 1970s".

Are you referring to an actual butter surplus or the eastern peak of Storm King Mountain in New York (Butter Hill, but known as Boterberg when the area was a Dutch colony)?