The Siege of Derry, the first major event in the Williamite War in Ireland, begins on April 18, 1689. The siege lasts nearly three and a half months, ending on July 30, 1689, when relief ships bringing the English Army sail down Lough Foyle.

The Glorious Revolution of 1688 is a relatively bloodless revolution in which James II, King of England, Ireland and Scotland and a Roman Catholic convert, is ousted from power by the Parliament of England. The English throne is then offered to his Protestant daughter Mary and her husband William III of England, also known as William of Orange. In Scotland, the privy council asks William III to assume responsibility for the government in January 1689, and he and Mary are formally offered the Scottish throne in March. The situation is different in Ireland where most of the population are Catholics. Irish Catholics are hoping that James will re-grant them lands, which had been seized from them after the Cromwellian conquest of Ireland (1649–53). James thus looks to Ireland to muster support in regaining his kingdoms just as his father, Charles I, had done in the English Civil War of the 1640s.

On December 10, James flees London. He is caught but flees a second time on December 23 and makes his way to France. On March 12, James I lands in Kinsale with 6,000 French soldiers. He takes Dublin and marches north with an army of Irish and French Catholics.

In April 1689 reinforcements from England arrive under the command of Colonel John Cunningham, who is a native of the city. He is under instructions to take his orders from the Derry City Governor, Lieutenant Colonel Robert Lundy. Lundy advises Colonel Cunningham to leave as arrangements have been made for the city to be surrendered. Lundy calls a meeting with several of his most loyal supporters to discuss surrender. News of the meeting spread, angering many of the citizens. That night, Lundy and many others leave the city aboard a ship to Scotland. The city’s defence is overseen by Major Henry Baker, Colonel Adam Murray, and Major George Walker, also an Anglican priest. Their slogan is “No Surrender.”

As the Jacobite army nears, all the buildings outside the city walls are set alight by the defenders to prevent them being used as cover by the besiegers.

The Jacobite army reaches Derry on April 18. James and his retinue ride to within 300 yards of Bishop’s Gate and demand the surrender of the city. He is rebuffed with shouts of “No surrender!” and some of the city’s defenders fire at him. James asks for surrender three more times but is refused each time. This marks the beginning of the siege. Cannon and mortar fire are exchanged, and disease takes hold within the city. James returns to Dublin and leaves his forces under the command of Richard Hamilton.

Royal Navy warships under Admiral George Rooke arrive in Lough Foyle on June 11 but initially decline to ram through the heavily defended defensive boom across the River Foyle at Culmore.

On July 28, two armed merchant ships, Mountjoy and Phoenix, sail toward the boom, protected by the frigate HMS Dartmouth under Captain John Leake. Mountjoy rams and breaches the boom, and the ships move in, unloading many tons of food to relieve the siege. The city had endured 105 days of siege during which some 4,000 Protestants of a population of 8,000 are said to have died.

The siege is commemorated yearly by the Protestant Apprentice Boys of Derry who stage the week-long Maiden City Festival culminating in a parade around the walls of the city by local members, followed by a parade of the city by the full Association. Although violence has attended these parades in the past, those in recent years have been largely peaceful.

The song “Derry’s Walls” is written to commemorate the siege.