Lonjsko polje (Lonja Field) is the largest nature park of central Croatia. It is situated in the valley of the river Sava, east of Zagreb, the capital of Croatia.
Nature park Lonjsko polje stretches over more than 500 km2 of protected area and it is one of the largest preserved wetlands of Europe. It is protected by the Ramsar Convention as a wetland area of world importance.
That which is most significant of Lonjsko Polje Nature Park is flooding which can occur any time of the year due to the extraordinary constellation of the Sava river. Flooding comes in huge waves and Lonjsko Polje plays a significant role as a flood system control of the area.
Accordingly, a great diversity of habitat is created in this area where many of the species are considered endangered both on national and international level.
Because of the abundance of bird species here, certain areas of the Park, such as Krapje Dol, Rakita and Draziblato areas, have been protected in the category of special ornithological reserves, while the entire Park is included in the List of important bird areas in Europe (IBA).