Derry is a city in Northern Ireland, located in County Londonderry. It sits at the estuary of the River Foyle and spans both sides of the river, with the historic walled city on the west bank (Cityside) and the Waterside on the east bank. The city is near the border with County Donegal in the Republic of Ireland. Derry is commonly referred to as Derry/Londonderry, with the latter name reflecting its administrative ties. If you’re looking for specifics like coordinates, population figures, or visitor information, I can provide them or look them up.