The old walled city of Londonderry lies on the west bank of the River Foyle, and the present city now covers both banks (Cityside to the west and Waterside to the east) and is connected by two bridges. Derry is the second-largest city in Northern Ireland, the fourth on the island of Ireland.

The city is currently officially named Londonderry according to the city's Royal Charter and usually appears as such on maps. The city is otherwise known as Derry, which is an anglicisation of the Irish Doire. Doire, means ‘Oak-grove’ and comes from the settlement's original name Daire Calgaich, translating as ‘oakwood of Calgach’. The name was changed from Derry in 1613 during the Plantation of Ulster to reflect the establishment of the city by the London guilds. However, most Irish people, at home and abroad, still prefer "Derry", so the proper name of the city remains a matter of dispute.

Planters organised by London livery companies through The Honourable Irish Society arrived in the 1600s as part of the plantation of Ulster, and built the walled city of Londonderry across the Foyle from the earlier town. The city has long been a focal point for important events in Irish history, including the 1688-1689 siege of Derry and Bloody Sunday on 30 January 1972.

Londonderry was the first ever planned city in Ireland: it was begun in 1613, with the walls being completed 5 years later in 1618. The central diamond within a walled city with four gates was thought to be a good design for defence. The modern city preserves the 17th-century layout of four main streets radiating from the Diamond to four gateways - Bishop's Gate, Ferryquay Gate, Shipquay Gate and Butcher's Gate.