The Lonja Field is a natural park that is located in the valley between the river Sava and the Mount Moslavina, 30km from the town of Sisak. The Lonjsko Polje is a protected area that extends over an area of 506 km2.
In Lonjsko Polje, flora and fauna are especially rich in bird in the reserve of Krapje Dol. In the park of Lonjsko Polje there are several rare species in Europe including eagles, herons, storks, etc.. Among the most practiced sports in Lonjsko Polje are bird watching, cycling, hiking, horseback riding, fishing and hunting.