Mount Logan (/ˈloʊɡən/ LOH-ghən) is the highest mountain in Canada, and the second-highest peak in North America after Denali (McKinley). The mountain was named after Sir William Edmond Logan, a Canadian geologist and founder of the Geological Survey of Canada (GSC). Mount Logan is located within Kluane National Park and Reserve in southwestern Yukon, less than 40 kilometres (25 miles) north of the Yukon–Alaska border. Mount Logan is the source of the Hubbard and Logan glaciers. Although many shield volcanoes are much larger in size and mass, Mount Logan is believed to have the largest base circumference of any non-volcanic mountain on Earth, including a massif with eleven peaks over 5,000 metres (16,000 feet). Mount Logan is the 6th most topographically prominent peak on Earth.

Due to active tectonic uplifting, Mount Logan is still rising in height (approximately 0.35 millimetres (0.014 in) per year). Before 1992, the exact elevation of Mount Logan was unknown and measurements ranged from 5,959 to 6,050 metres (19,551 to 19,849 ft). In May 1992, a GSC expedition climbed Mount Logan and fixed the current height of 5,959 metres (19,551 ft) using GPS.

Temperatures are extremely low on and near Mount Logan. On the 5,000-metre-high (16,000-foot; 5.0-kilometre) plateau, air temperature hovers around −45 °C (−49 °F) in the winter and reaches near freezing in summer with the median temperature for the year around −27 °C (−17 °F). Minimal snow melt leads to a significant ice cap, almost 300 metres (980 ft) thick in certain spots.

The Mount Logan massif is considered to contain all the surrounding peaks with less than 500 metres (1,600 ft) of prominence, as listed below:

Mount Logan is not readily visible from the surrounding lowlands or the coast, due to its position in the heart of the Saint Elias Mountains, although it can be seen from 201 kilometres (125 mi) out to sea. Pictures taken across Yakutat Bay to the south southeast suggest it is visible from near Yakutat. Its first reported sighting was in 1890 by American geologist Israel C. Russell, during an expedition to nearby Mount Saint Elias, from the crest of the Pinnacle Pass Hills (60°9.5′N 140°18′W / 60.1583°N 140.300°W / 60.1583; -140.300). Russel wrote: "The clouds parting toward the northeast revealed several giant peaks not before seen... One stranger, rising in three white domes far above the clouds, was especially magnificent". Russell gave the mountain its present name.

In 1894, Mount Logan's elevation was determined to be about 5,900 m (19,500 ft), making it the highest known peak in North America at the time. In 1898, Denali was determined to be higher.

In 1922, a geologist approached the Alpine Club of Canada with the suggestion that the club send a team to the mountain to reach the summit for the first time. An international team of Canadian, British and American climbers was assembled the following year, initially planning an attempt in 1924 but forced by funding and preparation delays to postpone the trip until 1925. The international team of climbers began their journey in early May, crossing the mainland from the Pacific coast by train. They then walked the remaining 200 km (120 mi) to within 10 km (6.2 mi) of the Logan Glacier where they established base camp. In the early evening of June 23, 1925, Albert H. MacCarthy (leader), H.F. Lambart, Allen Carpé, Norman H. Read, W.W. Foster, and Andy Taylor stood on top of the summit for the first time. It had taken them 65 days to approach the mountain from the nearest town (McCarthy across the border in Alaska), reach the summit, and return, with all climbers intact, although some of them suffered severe frostbite.

In January 2020, due to the cost of search and rescue operations in recent years, Parks Canada announced new rules for climbing Mount Logan: