I have a stupid question: If helium is so infeasable to extract from air or get from other chemical means. How did US end up with such had such a large supply of helium in the first place?

EDIT: The answer to the question is:

U.S. Bureau of Mines arranged for five private plants to recover helium from natural gas. For this helium conservation program, the Bureau built a 425-mile (684 km) pipeline from Bushton, Kansas to connect those plants with the government's partially depleted Cliffside gas field. This helium-nitrogen mixture was injected and stored in the Cliffside gas field until needed, when it then was further purified.