The Boundary Ranges, also known in the singular and as the Alaska Boundary Range, are the largest and most northerly subrange of the

Coast Mountains The Coast Mountains () are a major mountain range in the Pacific Coast Ranges of western North America, extending from southwestern Yukon through the Alaska Panhandle and virtually all of the British Columbia Coast, Coast of British Columbia sout ...

. They begin at the Nass River, near the southern end of the

Alaska Panhandle Southeast Alaska, often abbreviated to southeast or southeastern, and sometimes called the Alaska(n) panhandle, is the southeastern portion of the U.S. state of Alaska, bordered to the east and north by the northern half of the Canadian provi ...

in the

Canadian province Canada has ten provinces and three territories that are sub-national administrative divisions under the jurisdiction of the Constitution of Canada, Canadian Constitution. In the 1867 Canadian Confederation, three provinces of British North Amer ...

British Columbia British Columbia is the westernmost Provinces and territories of Canada, province of Canada. Situated in the Pacific Northwest between the Pacific Ocean and the Rocky Mountains, the province has a diverse geography, with rugged landscapes that ...

and run to the Kelsall River, near the Chilkoot Pass, beyond which are the Alsek Ranges of the Saint Elias Mountains, and northwards into the

Yukon Territory Yukon () is a territory of Canada, bordering British Columbia to the south, the Northwest Territories to the east, the Beaufort Sea to the north, and the U.S. state of Alaska to the west. It is Canada’s westernmost territory and the smallest ...

flanking the west side of the Yukon River drainage as far as Champagne Pass, north of which being the Yukon Ranges. To their east are the Skeena Mountains and Stikine Plateau of the Interior Mountains complex that lies northwest of the Interior Plateau; the immediately adjoining subregion of the Stikine Plateau is the

Tahltan Highland The Tahltan Highland is an upland area of plateau and relatively lower mountain ranges in British Columbia, Canada, lying east of the Boundary Ranges and south of the Inklin River (the east fork of the Taku River). Its eastern boundary is formed ...

. To their northeast is the Tagish Highland, which is a subregion of the Yukon Plateau. Both highlands are considered in some descriptions as included in the Coast Mountains. The

Alexander Archipelago The Alexander Archipelago () is a archipelago (group of islands) in North America lying off the southeastern coast of Alaska. It contains about 1,100 islands, the tops of submerged coastal mountains that rise steeply from the Pacific Ocean. Deep ...

lies offshore and is entirely within

Alaska Alaska ( ) is a non-contiguous U.S. state on the northwest extremity of North America. Part of the Western United States region, it is one of the two non-contiguous U.S. states, alongside Hawaii. Alaska is also considered to be the north ...

. The Boundary Ranges include several large icefields, including the

Juneau Icefield The Juneau Icefield is an ice field located just north of Juneau, Alaska, Juneau, Alaska, continuing north through the border with British Columbia, extending through an area of in the Coast Mountains, Coast Range ranging north to south and east ...

, between the Alaskan city of the same name and

Atlin Lake Atlin Lake (Tlingit language, Lingít: ''Áa Tlein'') is the largest natural lake in the Provinces and territories of Canada, Canadian province of British Columbia. The lake is wide and long. The northern tip of the lake is in the Yukon, as is ...

in B.C.; and the Stikine Icecap, which lies between the lower Stikine River and the Whiting River. Some of the highest mountains in the Boundary Ranges are: Mount Ratz, ; Chutine Peak, ; and Devils Thumb, , all in the Stikine Icecap region; and Devils Paw, , in the

. (Other peaks in the Stikine Icecap are higher than , but they have relatively low

topographic prominence In topography, prominence or relative height (also referred to as autonomous height, and shoulder drop in US English, and drop in British English) measures the height of a mountain or hill's summit relative to the lowest contour line encircling ...

.) Despite the height of Mount Ratz and its neighbours, most of the Boundary Ranges are considerably lower than the

Pacific Ranges The Pacific Ranges are the southernmost subdivision of the Coast Mountains portion of the Pacific Cordillera. Located entirely within British Columbia, British Columbia, Canada, they run northwest from the lower stretches of the Fraser River to B ...

of the southern

. The larger icefields of the Boundary Ranges are at a much lower elevation than their southern counterparts in the

because of the difference in latitude. Physiographically, they are a section of the larger Pacific Border province, which in turn is part of the larger Pacific Mountain System physiographic division. The

granitic A granitoid is a broad term referring to a diverse group of coarse-grained igneous rocks that are widely distributed across the globe, covering a significant portion of the Earth's exposed surface and constituting a large part of the continental ...

intrusion In geology, an igneous intrusion (or intrusive body or simply intrusion) is a body of intrusive igneous rock that forms by crystallization of magma slowly cooling below the surface of the Earth. Intrusions have a wide variety of forms and com ...

s that form the Boundary Ranges are remnants of a

Late Cretaceous The Late Cretaceous (100.5–66 Ma) is the more recent of two epochs into which the Cretaceous Period is divided in the geologic time scale. Rock strata from this epoch form the Upper Cretaceous Series. The Cretaceous is named after ''cre ...

volcanic arc A volcanic arc (also known as a magmatic arc) is a belt of volcanoes formed above a subducting oceanic tectonic plate, with the belt arranged in an arc shape as seen from above. Volcanic arcs typically parallel an oceanic trench, with the arc ...

system called the Coast Range Arc.

Subranges

* Boundary Range * Cheja Range * Chechidla Range * Chutine Icefield * Adam Mountains * Ashington Range * Burniston Range * Dezadeash Range * Florence Range * Halleck Range *

* Kahpo Mountains * Kakuhan Range * Lincoln Mountains * Longview Range * Peabody Mountains * Rousseau Range * Seward Mountains * Snowslide Range * Spectrum Range * Stikine Icecap

Rivers

Rivers draining or transiting the Boundary Ranges include the: * Chilkat River * Choquette River * Craig River * Iskut River * Kelsall River * Keta River * King Salmon Creek * Klehini River * Lava Fork * Nass River * Porcupine River * Salmon River * Scud River * Skagway River * Stikine River * Taiya River *

Taku River The Taku River (Tlingit language, Lingít: ''T'aaḵu Héeni'') is a river running from British Columbia, Canada, to the northwestern coast of North America, at Juneau, Alaska. The river basin spreads across . The Taku is a very productive salmon ...

* Tulsequah River * Unuk River * Whiting River

References

S. Holland, ''Landforms of British Columbia'', Province of British Columbia, 1976, pp 38-39

map from ''Bulletin 48: Landforms of British Columbia''
* *

External links

Boundary Ranges
of the Canadian Mountain Encyclopedia {{Coast Mountains Mountain ranges of British Columbia Physiographic sections

Subranges

Rivers

See also

References

External links