Department of Defense Alternative Energy Mapping Act - Requires the Secretary of Defense (DOD) to: (1) prepare maps of military installations and eligible adjacent property that classify locations on the installations and property as acceptable, unacceptable, or unassessed regarding their suitability for placement of geothermal, wind, solar photovoltaic, or solar thermal trough systems; (2) enter into agreements with entities involved in the production or installation of alternative energy systems to utilize their expertise and to share the costs of preparing such maps; and (3) disseminate such maps to Congress, the states in which the installations are located, local governments having jurisdiction over adjacent land, and the owners of adjacent private property.