Covering 7100 hectares, Biesbosch National Park encompasses an area on both banks of the Nieuwe Merwede River, east and south of Dordrecht. It's so big that it sprawls across a provincial border; there's a region known as the Brabantse Biesbosch, further east, while the part in this province is the Hollandse Biesbosch.
In 1970 the Delta Project shut off the tides to the area. Reeds, which had been growing wild, began to die, focusing attention on what is one of the largest expanses of natural space left in the Netherlands.
The park is home to beavers (reintroduced to the Brabant area of the park in 1988) and voles, along with scores of birds.