Cherbourg-Octeville is a city and former commune situated at the northern end of the Cotentin peninsula in the northwestern French department of Manche. Due to its union, it is the most populated city in its department with 37,121 inhabitants making it the first city of the department before the Saint-Lô prefecture and the second in the region after Caen.

Cherbourg-en-Cotentin is protected by Cherbourg Harbour, between La Hague and Val de Saire, and the city has been a strategic position over the centuries, disputed between the English and French. Cited as one of the "keys to the kingdom" by Vauban, it became, by colossal maritime development work, a first-rate military port under the leadership of Louis XVI and Napoleon, and holds an arsenal of the French Navy. A stopping point for prestigious transatlantic liners in the first half of the 20th century, Cherbourg was the primary goal of US troops during the invasion of Normandy in 1944.

Along with its use as a military, fishing and yachting port, it is also a cross-Channel ferry port, with routes to the English ports of Poole and Portsmouth, the Irish port of Rosslare Harbour and St Helier on Jersey. Limited by its geographical isolation from being a great commercial port, it is nonetheless an important shipbuilding centre, and a working-class city with a rural hinterland.