It is 6.58 km2 (2.54 sq mi) in size and is surrounded by marshes and brackish seepage lagoons.

[2] Haleji Lake was a saline lagoon until the 1930s and was converted into a reservoir to provide additional water to Karachi.

[2] During World War II, additional water was required for troops stationed at Karachi.

The then-British Government of Sindh Province decided to increase the capacity of the lake by introducing a feeder canal from the Indus River.

Haleji Lake is a wintering site for native and migratory waterfowl such as cotton teal, Indian spot-billed duck, purple moorhen and pheasant-tailed jacana.