The Battle of the Bogside was a large three-day riot that took place from 12 to 14 August 1969 in Derry, Northern Ireland. Thousands of Catholic/Irish nationalist residents of the Bogside, organised under the Derry Citizens' Defence Association, clashed with the Royal Ulster Constabulary (RUC) and loyalists, and sealed off the neighbourhood to authorities. It sparked widespread violence elsewhere in Northern Ireland, led to the deployment of British troops, and is often seen as the beginning of the thirty-year conflict known as the Troubles.
Violence broke out as the Protestant Apprentice Boys marched past the Catholic Bogside. The RUC drove back the Catholic crowd and pushed into the Bogside, followed by loyalists who attacked Catholic homes.