Lee Harvey Oswald (October 18, 1939 November 24, 1963) was a U.S. Marine veteran who assassinated John F. Kennedy, then president of the United States, on November 22, 1963.

Oswald was placed in juvenile detention at the age of 12 for truancy, during which time he was assessed by a psychiatrist as "emotionally disturbed", due to a lack of normal family life. After attending 22 schools in his youth, he quit repeatedly, and finally when he was 17, joined the Marines. Oswald was court-martialed twice while in the Marines, and jailed. He was honorably released from active duty in the Marine Corps into the reserve, then promptly flew to Europe and defected to the Soviet Union in October 1959. He lived in Minsk, Byelorussia, married a Russian woman named Marina, and had a daughter. In June 1962, he returned to the United States with his wife, and eventually settled in Dallas, where their second daughter was also born.

Oswald shot and killed Kennedy on November 22, 1963, from the sixth floor of the Texas School Book Depository as the President traveled by motorcade through Dealey Plaza in Dallas. About 45 minutes after assassinating Kennedy, Oswald shot and killed Dallas police officer J. D. Tippit on a local street. He then slipped into a movie theater, where he was arrested for Tippit's murder. Oswald was charged with the assassination of Kennedy, but he denied responsibility for the killing, claiming that he was a "patsy". Two days later, Oswald was fatally shot by local nightclub owner Jack Ruby on live television in the basement of Dallas Police Headquarters.

In September 1964, the Warren Commission concluded that Oswald had acted alone when assassinating Kennedy. This conclusion, though controversial, was supported by investigations from the Dallas Police Department, the Federal Bureau of Investigation (FBI), the United States Secret Service, and the House Select Committee on Assassinations.Despite forensic, ballistic, and eyewitness evidence supporting the official findings, public opinion polls have shown that most Americans still do not believe that the official version tells the whole truth of the events, and the assassination spawned numerous conspiracy theories.

Dallas () is a city in the U.S. state of Texas and the largest city in and seat of Dallas County, with portions extending into Collin, Denton, Kaufman and Rockwall counties. With a 2020 census population of 1,304,379, it is the ninth most-populous city in the U.S. and the third-largest in Texas after Houston and San Antonio. Located in North Texas, the city of Dallas is the main core of the largest metropolitan area in the Southern United States and the largest inland metropolitan area in the U.S. that lacks any navigable link to the sea. It is the most populous city in the Dallas–Fort Worth metroplex, the fourth-largest metropolitan area in the country at 7.5 million people.Dallas and nearby Fort Worth were initially developed due to the construction of major railroad lines through the area allowing access to cotton, cattle and later oil in North and East Texas. The construction of the Interstate Highway System reinforced Dallas's prominence as a transportation hub, with four major interstate highways converging in the city and a fifth interstate loop around it. Dallas then developed as a strong industrial and financial center and a major inland port, due to the convergence of major railroad lines, interstate highways and the construction of Dallas/Fort Worth International Airport, one of the largest and busiest airports in the world. In addition, Dallas has DART (Dallas Area Rapid Transit) with different colored train lines that transport throughout the Metroplex.Dominant sectors of its diverse economy include defense, financial services, information technology, telecommunications, and transportation. Dallas is home to nine Fortune 500 companies within the city limits while the Dallas–Fort Worth metroplex hosts twenty-two Fortune 500 companies, the second most in Texas and fourth most in the United States. Over 41 colleges and universities are located within its metropolitan area, which is the most of any metropolitan area in Texas. The city has a population from a myriad of ethnic and religious backgrounds and one of the largest LGBT communities in the U.S. WalletHub named Dallas the fifth most diverse city in the United States in 2018.