The Dennistoun Glacier is a glacier, 50 miles (80 km) long, draining the northern slopes of Mounts Black Prince, Royalist and Adam in the Admiralty Mountains of Victoria Land in Antarctica. It flows northwest between the Lyttelton Range and Dunedin Range, turning east on rounding the latter range to enter the sea south of Cape Scott. The coastal extremity of the glacier was charted in 1911–12 by the Northern Party, led by Victor Campbell, of the British Antarctic Expedition, 1910–13. The geographical feature lies situated on the Pennell Coast, a portion of Antarctica lying between Cape Williams and Cape Adare.