The West Northwall Firn was a glacial body on Mount Carstensz in the Sudirman Range on the island of New Guinea in Central Papua province, Indonesia.

The glacier was situated at an elevation of approximately 4,600 metres (15,100 ft) to 4,750 metres (15,580 ft), centered a little over 3 kilometres (1.9 mi) northwest of Ngga Pulu and 5 kilometres (3.1 mi) of Puncak Jaya (Carstensz Pyramid), the highest peak of Oceania.

Research presented in 2004 of IKONOS satellite imagery of the New Guinean glaciers indicated that in the two years from 2000 to 2002, the West Northwall Firn had lost a further 19.4% of its surface area.

[4] The West Northwall Firn was a remnant glacier of an icecap that in 1850 measured about 20 km2 (7.7 sq mi) and had developed approximately 5,000 years ago.

At least one previous icecap also existed in the region between 15,000 and 7,000 years ago, when it also apparently melted away and disappeared.