It was constructed in the late 1970s to relieve congestion at Karachi Port. Port Qasim was named after the Muslim general Muhammad bin Qasim who captured the area around 712 CE. The port was developed close to the Pakistan Steel Mills complex near the Indus River delta. Port Qasim's residential area is a neighbourhood of Bin Qasim Town of Karachi.
Port Qasim is managed by Port Qasim Authority. It is Pakistan's second busiest port, handling about 35% of the nation's cargo (17 million tons per annum). It is located in an old channel of the Indus River at a distance of 35 kilometres east of Karachi city centre. The total area of the port comprises 1,000 acres (4 km²) with an adjacent 11,000 acre (45 km²) industrial estate. The approach to the port is along a 45-kilometre long Navigation Channel which provides safe navigation for vessels up to . The geographic position of the Port places it in close proximity to major shipping routes. One of its major advantages is the proximity to national transport facilities - 15 kilometres from the Pakistan National Highway, 14 kilometres from the National Railway network through six railway tracks located immediately behind the berths and 22 kilometres from Jinnah International Airport.
The tidal variation at the mouth as well as in the port is between 0.5 to 3.5 m. The port is not only accessible through sea but is also well connected with the hinterland, through road and railway networks.
The beach immediately west of the navigation channel was the scene of a major oil spillage when the Greek-registered Tasman Spirit ran aground in August 2003. The environmental impact included large numbers of dead fish and turtles and a key mangrove forest, as well as dozens of people suffering nausea.