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 (french: La chaîne Côtière) 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 Coast of British Columbi ...
. They begin at the Nass River, near the southern end of the
Alaska Panhandle
Southeast Alaska, colloquially referred to as 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 province of British Columbia (and a small part ...
in the
Canadian province
Within the geographical areas of Canada, the ten provinces and three territories are sub-national administrative divisions under the jurisdiction of the Canadian Constitution. In the 1867 Canadian Confederation, three provinces of British Nor ...
of
British Columbia
British Columbia (commonly abbreviated as BC) is the westernmost province of Canada, situated between the Pacific Ocean and the Rocky Mountains. It has a diverse geography, with rugged landscapes that include rocky coastlines, sandy beaches, for ...
Saint Elias Mountains
The Saint Elias Mountains (french: Chaîne Saint-Élie) are a subgroup of the Pacific Coast Ranges, located in southeastern Alaska in the United States, Southwestern Yukon and the very far northwestern part of British Columbia in Canada. The r ...
, and northwards into the
Yukon Territory
Yukon (; ; formerly called Yukon Territory and also referred to as the Yukon) is the smallest and westernmost of Canada's three territories. It also is the second-least populated province or territory in Canada, with a population of 43,964 as ...
flanking the west side of the Yukon River drainage as far as Champagne Pass, north of which being the
Yukon Ranges
The Yukon Ranges are a mountain range comprising the mountains in the southeastern part of the U.S. state of Alaska and most of the Yukon in Canada. Named after the Yukon, this range has area of .Skeena Mountains and
Stikine Plateau
The Stikine Plateau is a plateau in northern British Columbia, Canada. It lies between the Boundary Ranges of the Coast Mountains on the west and southwest and the Cassiar Mountains along its northeast, and between the Skeena Mountains on its south ...
of the
Interior Mountains
The Interior Mountains or Northern Interior Mountains are the semi-official names for an expansive collection of mountain ranges that comprises much of the northern half of the Canadian province of British Columbia and a large area of southern Y ...
complex that lies northwest of the Interior Plateau; the immediately adjoining subregion of the Stikine Plateau is the Tahltan Highland. To their northeast is the Tagish Highland, which is a subregion of the
Yukon Plateau
The Yukon Plateau is a plateau (also defined as a plain) located in the Yukon Territory, comprising much of the central and southern Yukon Territory and the far northern part of British Columbia, Canada between Tagish Lake (W) and the Cassiar Moun ...
. Both highlands are considered in some descriptions as included in the Coast Mountains. The
Alexander Archipelago
The Alexander Archipelago (russian: Архипелаг Александра) is a long 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 m ...
lies offshore and is entirely within
Alaska
Alaska ( ; russian: Аляска, Alyaska; ale, Alax̂sxax̂; ; ems, Alas'kaaq; Yup'ik: ''Alaskaq''; tli, Anáaski) is a state located in the Western United States on the northwest extremity of North America. A semi-exclave of the U ...
.
The Boundary Ranges include several large icefields, including the Juneau Icefield, between the Alaskan city of the same name and Atlin Lake in B.C.; and the
Stikine Icecap
The Stikine Icecap (sometimes referred to as the Stikine Icefield) is a large icefield straddled on the Alaska– British Columbia boundary in the Alaska Panhandle region. It lies in the Boundary Ranges of the Coast Mountains. Within the Unite ...
, which lies between the lower Stikine River and the
Whiting River
The Whiting River is a stream, about long, in the U.S. state of Alaska and the Canadian province of British Columbia. It enters the waters of Stephens Passage at the Borough of Juneau in the Alaska Panhandle between the mouths of the Taku and St ...
. Some of the highest mountains in the Boundary Ranges are:
Mount Ratz
Mount Ratz is a mountain located just west of the Stikine River, about east of the British Columbia-Alaska border. It is the highest peak in the Stikine Icecap and of the Boundary Ranges which in turn form part of the Coast Mountains. It is an ...
, ;
Chutine Peak
Chutine Peak is one of the highest mountains in the Boundary Ranges, a group of subranges of the northern Coast Mountains of British Columbia and Alaska. Chutine Peak lies just east of the Stikine Icecap, and to the north and west of the Stikine ...
, ; and
Devils Thumb
Devils Thumb, or Taalkhunaxhkʼu Shaa in Tlingit, is a mountain in the Stikine Icecap region of the Alaska–British Columbia border, near Petersburg. It is named for its projected thumb-like appearance. Its name in the Tlingit language means " ...
, , all in the
Stikine Icecap
The Stikine Icecap (sometimes referred to as the Stikine Icefield) is a large icefield straddled on the Alaska– British Columbia boundary in the Alaska Panhandle region. It lies in the Boundary Ranges of the Coast Mountains. Within the Unite ...
Stikine Icecap
The Stikine Icecap (sometimes referred to as the Stikine Icefield) is a large icefield straddled on the Alaska– British Columbia boundary in the Alaska Panhandle region. It lies in the Boundary Ranges of the Coast Mountains. Within the Unite ...
are higher than , but they have relatively low
topographic prominence
In topography, prominence (also referred to as autonomous height, relative height, and shoulder drop in US English, and drop or relative height in British English) measures the height of a mountain or hill's summit relative to the lowest contou ...
.)
Despite the height of
Mount Ratz
Mount Ratz is a mountain located just west of the Stikine River, about east of the British Columbia-Alaska border. It is the highest peak in the Stikine Icecap and of the Boundary Ranges which in turn form part of the Coast Mountains. It is an ...
and its neighbours, most of the Boundary Ranges are considerably lower than the
Pacific Ranges
, photo = Mount Garibaldi (50997016501).jpg
, photo_size = 280px
, photo_caption = Mount Garibaldi massif as seen from Squamish
, map =
, map_image = South BC-NW USA-relief PacificRanges.png
, ...
of the southern
Coast Mountains
The Coast Mountains (french: La chaîne Côtière) 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 Coast of British Columbi ...
. The larger icefields of the Boundary Ranges are at a much lower elevation than their southern counterparts in the
Pacific Ranges
, photo = Mount Garibaldi (50997016501).jpg
, photo_size = 280px
, photo_caption = Mount Garibaldi massif as seen from Squamish
, map =
, map_image = South BC-NW USA-relief PacificRanges.png
, ...
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
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 younger 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 ''creta'', ...
Coast Range Arc
The Coast Range Arc was a large volcanic arc system, extending from northern Washington through British Columbia and the Alaska Panhandle to southwestern Yukon. The Coast Range Arc lies along the western margin of the North American Plate in the ...
Chechidla Range
The Chechidla Range is a mountain range in northernwestern British Columbia, Canada, located about west of Dease Lake and 125–150 km south-southeast of Atlin. It has an area of 3236 km2 and lies roughly in between the Whiting and ...
Spectrum Range
The Spectrum Range, formerly called the Spectrum Mountains and the Rainbow Mountains, is a subrange of the Tahltan Highland in the Stikine Country of northwestern British Columbia, 20 km west of the Stewart-Cassiar Highway, south of Mount ...
*
Stikine Icecap
The Stikine Icecap (sometimes referred to as the Stikine Icefield) is a large icefield straddled on the Alaska– British Columbia boundary in the Alaska Panhandle region. It lies in the Boundary Ranges of the Coast Mountains. Within the Unite ...
Rivers
Rivers draining or transiting the Boundary Ranges include the:
*
Chilkat River
The Chilkat River is a river in British Columbia and southeastern Alaska that flows southward from the Coast Range to the Chilkat Inlet and ultimately Lynn Canal. It is about long. It begins at Chilkat Glacier, in Alaska, flows west and south ...
Craig River
The Craig River is a transboundary river tributary of the Iskut River in Southeast Alaska, United States, and the northwest part of the province of British Columbia, Canada. Originating in Alaska, where it is sometimes called the South Fork Craig ...
Klehini River
The Klehini River is a large, glacially fed stream in the vicinity of Haines in the U.S. state of Alaska.
The Klehini River is about long from its source in British Columbia to its mouth at the Chilkat River, of which it is the largest tribut ...
*
Lava Fork
Lava Fork is a creek in northwestern British Columbia, Canada and of the Alaska Panhandle, United States. It lies west of the Unuk River and northwest of Stewart. It flows south from the Lava Lakes across the British Columbia-Alaska border int ...
Taku River
The Taku River ( 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 river and its d ...
*
Tulsequah River The Tulsequah River, formerly the Talsekwe River ( Lingít: ''Taaltsux̱éi''), is a tributary of the Taku River in northwestern British Columbia, located south of the Atlin District and inland from Juneau, Alaska
The City and Borough of June ...
*
Unuk River
The Unuk River is a river in the U.S. state of Alaska and the Canadian province of British Columbia. It flows from the Coast Mountains southwest to Behm Canal, northeast of Ketchikan, Alaska.
From its headwaters in a heavily glaciated area in Bri ...
*
Whiting River
The Whiting River is a stream, about long, in the U.S. state of Alaska and the Canadian province of British Columbia. It enters the waters of Stephens Passage at the Borough of Juneau in the Alaska Panhandle between the mouths of the Taku and St ...