The new site was purchased from longtime owner HP, which is in the process of consolidating operations at its headquarters in Palo Alto.
The existing buildings are relatively old, leading to speculation that Apple may embark on a major rebuilding program.
The purchase follows rapid growth in Apple's workforce. The company reported 46,600 full-time equivalent (FTE) employees and 2800 FTE temps and contractors as at September 25, 2010, approximately one-third more than in 2009.
While headcounts have grown at other locations (for example, a further 44 Apple Stores were opened during the year), it is understood that many of the new hires are based in and around Cupertino.
Apple has been based in Cupertino for almost all of its history. Co-founder and CEO Steve Jobs attended schools in the area.