The shift to the Cheyenne Mountain base in Colorado is designed to safeguard the command's sensitive sensors and servers from a potential electromagnetic pulse (EMP) attack, military officers said.
The Pentagon last week announced a $700 million contract with Raytheon Corporation to oversee the work for North American Aerospace Command (NORAD) and US Northern Command.
Admiral William Gortney, head of NORAD and Northern Command, said that "because of the very nature of the way that Cheyenne Mountain's built, it's EMP-hardened."
"And so, there's a lot of movement to put capability into Cheyenne Mountain and to be able to communicate in there," Gortney told reporters.
"My primary concern was... are we going to have the space inside the mountain for everybody who wants to move in there, and I'm not at liberty to discuss who's moving in there," he said.
"A lot of the back office communications is being moved there," said one defense official.
Officials said the military's dependence on computer networks and digital communications makes it much more vulnerable to an electromagnetic pulse, which can occur naturally or result from a high-altitude nuclear explosion.