The Callaghan Valley is located in the Sea to Sky Country of southwestern, British Columbia, in the Pacific Ranges of the Coast Mountains 90 km north of Vancouver.
On its western perimeter is the Powder Mountain Icefield, and the potentially active[1][2] volcano Mount Cayley, which lies at the valley's southwestern extremity.
The valley's mouth and road access is at McGuire's on BC Highway 99, 14 kilometres south of downtown Whistler, in British Columbia.
The location is also known as Northair, and the road as the Northair Mine Road, after a mine located a few miles north of the junction, which is marked by a quarry pit columnar basalt lava rock on the opposite side of the highway, and which are the northern end of a small lava plateau between the highway and river south to and including Brandywine Falls.
Volcanoes in the Callaghan Valley were erupted between 25,000 and 11,000 years ago whose age is extremely young in the geologic record.