For the purposes of this report, terrorism is defined as 'the unlawful use of force or violence against persons or property to intimidate or coerce a government, the civilian population, or any segment thereof, in furtherance of political or social objectives.' A terrorist incident is defined as 'a violent act or an act dangerous to human life in violation of the criminal laws of the United States or of any State to intimidate or coerce a government, the civilian population, or any segment thereof, in furtherance of political or social objectives.' The graphical display of terrorist incidents in the United States for 1983 includes (1) a chronological list of terrorist incidents, (2) terrorist incidents by type, (3) terrorist incidents by group and type, and (4) a U.S. map of terrorist incidents. A comparison of terrorist incidents for 1979-83 presents terrorist incidents by targets for 1982-83, comparison by terrorist group (1982-83), comparison by type (1982-82), total number of terrorist incidents (1979-83), total number killed and injured (1979-83), terrorist incidents and bombings (1979-83), terrorist incidents by region (1979-83), and comparison by trends in terrorist activity. The summaries of domestic groups or individuals responsible for terrorist incidents in 1983 cover the incidents perpetrated by the Jewish Defense League, the Ejercito Popular Boricua -Macheteros (Puerto Rican group), and the following groups: Armed Resistance Unit, Frente Farabudno Marti de Liberacion Nacional, Republic of Revolutionary, Revolutionary Fighting Group, Sheriff's Posse Comitatus, United Freedom Front, and Fugra (an unknown group). Individual terrorist incidents are reported for Carlos Martinez and Hossein Olya. Summaries are also presented for international groups of persons responsible for terrorist incidents in 1983. Major law enforcement accomplisments against terrorism, both domestic and international, are described for 1983.