While volcanism has persisted here for some 1.5 million years, the current glaciated cone is likely no more than 140,000 years old, and possibly no older than 80–90,000 years. Older volcanic edifices have mostly eroded away due to glaciation.
After Mount Rainier, Mount Baker is the most heavily glaciated of the Cascade Range volcanoes; the volume of snow and ice on Mount Baker, 0.43 cu mi (1.79 km3) is greater than that of all the other Cascades volcanoes (except Rainier) combined. It is also one of the snowiest places in the world; in 1999, Mount Baker Ski Area, located 14 km (8.7 mi) to the northeast, set the world record for recorded snowfall in a single season—1,140 in (2,900 cm).
At 10,781 ft (3,286 m), it is the third-highest mountain in Washington State and the fifth-highest in the Cascade Range, if Little Tahoma Peak, a subpeak of Mount Rainier, and Shastina, a subpeak of Mount Shasta, are not counted. Located in the Mount Baker Wilderness, it is visible from much of Greater Victoria, Nanaimo, and Greater Vancouver in British Columbia and, to the south, from Seattle (and on clear days Tacoma) in Washington.
Indigenous Peoples have known the mountain for thousands of years, but the first written record of the mountain is from Spanish explorer Gonzalo Lopez de Haro, who mapped it in 1790 as Gran Montaña del Carmelo, "Great Mount Carmel". The explorer George Vancouver renamed the mountain for 3rd Lieutenant Joseph Baker of HMS Discovery, who saw it on April 30, 1792.