The Ardglen Tunnel, also called the Liverpool Range tunnel, is a heritage-listed summit rail tunnel located on the Main North railway between Ardglen in the Liverpool Plains Shire and Murrurundi in the Upper Hunter Shire local government area, both in New South Wales, Australia. The tunnel crosses under the Liverpool Range near its east end, below Nowlands Gap (otherwise known as Murrurundi Gap), the crossing used by the New England Highway, and provides a vital link between Newcastle and Werris Creek. The tunnel was completed in 1877 and is owned by the Transport Asset Holding Entity, a state-owned corporation of the Government of New South Wales. It was added to the New South Wales State Heritage Register on 2 April 1999.