Fort Drum is a census-designated place and U.S. Army military reservation in Jefferson County, New York, United States. The population was 12,955 at the 2010 census. It is home to the 10th Mountain Division. Fort Drum consists of 107,265 acres (434 km²). Its mission includes command of active component units assigned to the installation, provide administrative and logistical support to tenant units, support to tenant units, support to active and reserve units from all services in training at Fort Drum, and planning and support for the mobilization and training of almost 80,000 troops annually.