Den Helder is a municipality and a city in the Netherlands, in the province of North Holland. Den Helder occupies the northernmost point of the North Holland peninsula. It is home to the country’s main naval base. From here the Royal TESO ferryboat service operates the transportation link between Den Helder and the nearby Dutch Wadden island of Texel to the north.

The municipality of Den Helder consists of the following cities, towns, villages and/or districts: Den Helder, Huisduinen, Julianadorp, and the hamlets Friese Buurt and De Kooy.

The major areas of Den Helder are Old Den Helder, Nieuw-Den Helder, and De Schooten. Nieuw-Den Helder was built in the 1950s, following World War II, when there was a great need for additional housing. De Schooten was constructed in the 1960s.

Den Helder was the site of a naval base as early as the 18th century. An Anglo-Russian invasion force landed at Den Helder in August 1799 and captured the Batavian navy there (see Battle of Castricum). French emperor Napoleon Bonaparte, visiting Den Helder in 1811, was impressed with the town’s strategic location and ordered the construction of a fort (Kijkduin) and naval dockyards (Willemsoord). The docks were built during the years 1813–1827. In 1947, it officially became the Royal Netherlands Navy’s main centre of operations. Den Helder continues to be the navy’s main base today. The Royal Netherlands Naval College is also located in the city, as is the Dutch Navy Museum.

The old naval dockyards of Willemsoord, located in the north of the city, now house restaurants, a cinema, and other recreational facilities. The naval docks and administration have been moved to a new location further east.