James Joseph "Whitey" Bulger Jr. (/ˈbʌldʒər/ ^ⓘ; September 3, 1929 – October 30, 2018) was an American organized crime boss who led the Winter Hill Gang, an Irish mob group based in the Winter Hill neighborhood of Somerville, Massachusetts, northwest of Boston. On December 23, 1994, Bulger went into hiding after his former FBI handler, John Connolly, tipped him off about a pending RICO indictment against him. He remained at large for 16 years. After his 2011 arrest, federal prosecutors tried Bulger for 19 murders based on grand jury testimony from Kevin Weeks and other former criminal associates.

Although he adamantly denied it, the FBI stated that Bulger had served as an informant for several years starting in 1975, providing information about the inner workings of the Patriarca crime family, his Italian-American Mafia rivals based in Boston and Providence, Rhode Island. In return, Connolly, as Bulger's FBI handler, ensured that the Winter Hill Gang was effectively ignored. Beginning in 1997, press reports exposed various instances of criminal misconduct by federal, state and local officials with ties to Bulger, causing embarrassment to several government agencies, especially the FBI.

Five years after his flight from the Boston area, Bulger was added to the FBI's Ten Most Wanted Fugitives list; he was considered the most wanted person on the list behind Osama bin Laden. Another 12 years passed before he was apprehended along with his longtime girlfriend, Catherine Greig, outside an apartment complex in Santa Monica, California. Bulger and Greig were extradited to Boston and taken to court under heavy guard. In June 2012, Greig pleaded guilty to conspiracy to harbor a fugitive, identity fraud, and conspiracy to commit identity fraud, receiving a sentence of eight years in prison. Bulger declined to seek bail and remained in custody.

Bulger's trial began in June 2013. He was tried on 32 counts of racketeering, money laundering, extortion, and weapons charges, including complicity in 19 murders. On August 12, Bulger was found guilty on 31 counts, including both racketeering charges, and was found to have been involved in 11 murders. On November 14, he was sentenced to two consecutive life sentences plus five years by U.S. District Court Judge Denise J. Casper. Bulger was incarcerated at the United States Penitentiary Coleman II in Sumterville, Florida.

Bulger was transferred to several facilities in October 2018; first to the Federal Transfer Center in Oklahoma and then to the United States Penitentiary, Hazelton, near Bruceton Mills, West Virginia. Bulger, who was in a wheelchair, was beaten to death by inmates on October 30, 2018, within hours of his arrival at Hazelton. In 2022, Fotios Geas, Paul DeCologero and Sean McKinnon were charged with conspiracy to commit first-degree murder in Bulger's death.

Whitey Bulger's father, James Joseph Bulger Sr., hailed from Harbour Grace, Newfoundland, the son of Irish parents. After settling in Everett, Massachusetts, he married Jane Veronica "Jean" McCarthy, a first-generation Irish immigrant. The second of six children, James Joseph Bulger Jr., was born on September 3, 1929. The family moved to Boston shortly after his birth.

Bulger's father worked as a union laborer and occasional longshoreman. He lost his arm in an industrial accident and the family was reduced to poverty. In May 1938, the Mary Ellen McCormack Housing Project was opened in the neighborhood of South Boston. The Bulger family moved in and the children grew up there. While his younger siblings, William Bulger and John P. Bulger, excelled at school, James Bulger Jr. was drawn into street life.

Early in his criminal career, local police gave Bulger the nickname "Whitey" because of his blond hair. Bulger hated the name; he preferred to be called "Jim", "Jimmy", or even "Boots". The last nickname came from his habit of wearing cowboy boots, in which he used to hide a switchblade.