Cherbourg-en-Cotentin is a port city in the department of Manche, Normandy, northwestern France, established on 1 January 2016. The commune takes its name from Cherbourg, the main town of the commune, and the Cotentin Peninsula. Cherbourg is an important commercial, ferry and military port on the English Channel. Cherbourg-en-Cotentin is a Maritime prefecture and sub-prefecture of Manche. Due to its union, it is the most populous commune in its department with 79,144 inhabitants as of 2018, making it the first city of the department before the Saint-Lô prefecture and the second in the region after Caen. Its urban unit is composed of three communes, and has 81,963 inhabitants (2018). Its larger functional area has 152,630 inhabitants (2018).

Manche is a coastal French département in Normandy on the English Channel, which is known as La Manche, literally "the sleeve", in French. Manche is bordered by Ille-et-Vilaine and Mayenne to the south, Orne and Calvados to the east, the English Channel to the west and north and by sharing maritime borders with the Crown Dependencies of Bailiwick of Jersey and Bailiwick of Guernsey of the United Kingdom to the west. It had a population of 495,045 in 2019.