The Defence Infrastructure Organisation (DIO) is an executive agency of the United Kingdom's Ministry of Defence, responsible for managing and maintaining the defence estate, including military bases, training grounds, and associated facilities. It was established in April 2011 following the merger of Defence Estates and several other property management bodies, making it one of the largest property managers in the United Kingdom. The DIO's headquarters are located at Aldershot Garrison, which was designated the primary administrative site for defence estate management following a 2009 Parliamentary review.