Trị An lake it's a man-made lake with an area of 323 square kilometres built in 1987. Located in the course of the Đồng Nai River and stretches over several districts of Đồng Nai Province. The green algae blooms during the low water season from July to October. The sight of fishing boats cutting through a sea of green algae is probably the most iconic image of Trị An Lake.