The Troubles () was a guerrilla/nationalist conflict in Northern Ireland during the late 20th century.
It is also known as the Northern Ireland conflict, it is sometimes described as an "irregular war" or "low-level war".
The conflict began in the late 1960s and many said it ended with the Good Friday Agreement of 1998. Although the Troubles primarily took place in Northern Ireland, at times the violence spilled over into parts of the Republic of Ireland, England, and mainland Europe.
A key issue was the state of Northern Ireland. Unionists/loyalists (most of whom were Protestants) wanted Northern Ireland to remain within the United Kingdom. Irish nationalists/republicans (most of whom were Catholics) wanted Northern Ireland to leave the United Kingdom and join a United Ireland.
More than 3,500 people were killed in the conflict. Of those: 52% were civilians, 32% were members of the British security forces, and 16% were members of paramilitary groups.