The town was founded in 1827, but there were settlements at the place as early as the 12th century. These tiny villages were built on small islands in the swampy estuary. There have been early plans to found a fortified town at the place in order to protect the ships leaving or entering the Weser. In 1672 Swedish colonists tried to erect a castle (Carlsburg), but they failed.
It was not managed before 1827 to carry out the plan. The city of Bremen bought the territories at the Weser mouth from the kingdom of Hanover. Bremerhaven was born and became a second harbour to Bremen, despite the distance of 50 km between the places. Due to the trade with and the emigration to North America the port and the town grew fast.
The kingdom of Hanover founded a rivalling town directly beside Bremerhaven and called it Geestemünde (1845). Both towns grew and established the three pillars of trade, shipbuilding and fishing. In 1927 Geestemünde and some neighbouring municipalities were united to become the new city of Wesermünde, and in 1939 Wesermünde and Bremerhaven were merged. The town and the port were destroyed in World War II; in 1947 it became a part of the Bundesland of Bremen. Today Bremerhaven is not (as sometimes believed) a part of the city of Bremen, but an autonomous city.
Bremerhaven has no historical buildings, and the city centre is absolutely new. The main attractions for tourists are a ship museum, a historical harbour and an aquarium (the "Atlanticum").