Air defense identification zone

An air defense identification zone (ADIZ) is a region of airspace in which a country tries to identify, locate, and control aircraft in the interest of national security. It is declared unilaterally and may extend beyond a country's territory to give the country more time to respond to possibly hostile aircraft. The concept of an ADIZ is not defined in any international treaty and is not recognized by any international body.

The first ADIZ was established by the United States on December 27, 1950, shortly after President Truman had proclaimed a national emergency during the Korean War. About 20 countries and regions now have such zones, including Canada, India, Japan, Pakistan, Bangladesh, Finland, Norway, the United Kingdom, the People's Republic of China, South Korea, Taiwan, United States, Sweden, Iceland, and Iran. As well, Russia and North Korea have unofficial zones. Usually, such zones cover only undisputed territory, do not apply to foreign aircraft not intending to enter territorial airspace, and do not overlap.

Air defense zones should not be confused with flight information regions (FIRs), which are used to manage air traffic.