CATAWBA COUNTY, N.C. -- The largest Apple Data Center is located in Catawba County, and it's getting bigger.

Building permits filed with the county show a $22 million expansion to its site in Maiden on Startown Road, a town of just a little more than 3,000 people.

Scott Millar, President of Catawba County's Economic Development, says the company committed in 2009 to spending $1 billion and employing 150 people.

"Fast forward to 2017, they have already spend over $4 billion," said Millar. "And they've got over 400 people on campus permanently."

The project is three times the size of a football field, which is more than 200,000 square feet.