Mafia III takes place during the late 1960s, within the fictional U.S. city of New Bordeaux. Situated within America's southern states and coastline, the city is composed of island districts, industrial complexes and ports, high-rise offices and apartments, slums, suburban housing, and historical districts, interconnected by railroads and an extensive road network, with a large swampland separating the city from the coast. The city consists of a mixture of cultures including African Americans, Irish, Italians and Haitians, and is mostly controlled by one Mafia crime family – the Marcano family – alongside smaller organisations like the Irish Mob, the Haitian Mob, the Black Mob, and the Southern Union, a group of white supremacists. The game takes place in the year of 1968, and revolves around Lincoln Clay, a biracial orphan and Vietnam veteran. As an orphan, he was constantly looking for a family, until he joins the armed forces and fights in the Vietnam War. He returns to New Orleans, after the war and he joins "The Black Mob". After surviving a murder attempt by the Italian Mob, Clay attempts to start his own criminal organization and get revenge.
Source: Wikipedia, "Mafia III", available under the CC-BY-SA License.