The Gates of the Mountains Wilderness is located in the U.S. state

U.S. state

A U.S. state is any one of the 50 federated states of the United States of America that share sovereignty with the federal government. Because of this shared sovereignty, an American is a citizen both of the federal entity and of his or her state of domicile. Four states use the official title of...

 of Montana

Montana

Montana is a state in the Western United States. The western third of Montana contains numerous mountain ranges. Smaller, "island ranges" are found in the central third of the state, for a total of 77 named ranges of the Rocky Mountains. This geographical fact is reflected in the state's name,...

. Created by an act of Congress in 1964, the wilderness is managed by Helena National Forest

Helena National Forest

Helena National Forest is located in west-central Montana, in the United States. Covering 976,000 acres , the forest is broken into several separate sections. The eastern regions are dominated by the Big Belt Mountains, and are the location of the Gates of the Mountains Wilderness, which remains...

. A day use campground near the Gates of the Mountains, Meriwether Picnic site, is named in honor of Meriwether Lewis

Meriwether Lewis

Meriwether Lewis was an American explorer, soldier, and public administrator, best known for his role as the leader of the Lewis and Clark Expedition also known as the Corps of Discovery, with William Clark...

.

Gates of the Mountains Wilderness (then known as the Gates of the Mountains Wild Area) was the site of the 1949 Mann Gulch fire

Mann Gulch fire

The Mann Gulch fire of 1949 was a wildfire in the Helena National Forest, Montana, United States, which claimed the lives of 13 firefighters including 12 smoke jumpers who were parachuted into the area to fight the fire, but were unable to control it....

, which claimed the lives of 13 firefighters and which was the subject of Norman Maclean

Norman Maclean

Norman Fitzroy Maclean was an American author and scholar noted for his books A River Runs Through It and Other Stories and Young Men and Fire .-Biography:...

's book Young Men and Fire

Young Men and Fire

Young Men and Fire is a non-fiction book written by Norman Maclean. It is an account of Norman Maclean's research of the Mann Gulch fire of 1949 and the 13 men who died there. The fire occurred in Mann Gulch in the Gates of the Mountains Wilderness on August 5...

.

U.S. Wilderness Areas do not allow motorized or mechanized

Mechanization

Mechanization or mechanisation is providing human operators with machinery that assists them with the muscular requirements of work or displaces muscular work. In some fields, mechanization includes the use of hand tools...

 vehicles, including bicycle

Bicycle

A bicycle, also known as a bike, pushbike or cycle, is a human-powered, pedal-driven, single-track vehicle, having two wheels attached to a frame, one behind the other. A person who rides a bicycle is called a cyclist, or bicyclist....

s. Although camping

Camping

Camping is an outdoor recreational activity. The participants leave urban areas, their home region, or civilization and enjoy nature while spending one or several nights outdoors, usually at a campsite. Camping may involve the use of a tent, caravan, motorhome, cabin, a primitive structure, or no...

 and fishing

Fishing

Fishing is the activity of trying to catch wild fish. Fish are normally caught in the wild. Techniques for catching fish include hand gathering, spearing, netting, angling and trapping....

 are allowed with proper permit, no roads or buildings are constructed and there is also no logging

Forestry

Forestry is the interdisciplinary profession embracing the science, art, and craft of creating, managing, using, and conserving forests and associated resources in a sustainable manner to meet desired goals, needs, and values for human benefit. Forestry is practiced in plantations and natural stands...

 or mining

Mining

Mining is the extraction of valuable minerals or other geological materials from the earth, from an ore body, vein or seam. The term also includes the removal of soil. Materials recovered by mining include base metals, precious metals, iron, uranium, coal, diamonds, limestone, oil shale, rock...

, in compliance with the 1964 Wilderness Act

Wilderness Act

The Wilderness Act of 1964 was written by Howard Zahniser of The Wilderness Society. It created the legal definition of wilderness in the United States, and protected some 9 million acres of federal land. The result of a long effort to protect federal wilderness, the Wilderness Act was signed...

. Wilderness areas within National Forests

United States National Forest

National Forest is a classification of federal lands in the United States.National Forests are largely forest and woodland areas owned by the federal government and managed by the United States Forest Service, part of the United States Department of Agriculture. Land management of these areas...

 and Bureau of Land Management

Bureau of Land Management

The Bureau of Land Management is an agency within the United States Department of the Interior which administers America's public lands, totaling approximately , or one-eighth of the landmass of the country. The BLM also manages of subsurface mineral estate underlying federal, state and private...

 areas also allow hunting

Hunting

Hunting is the practice of pursuing any living thing, usually wildlife, for food, recreation, or trade. In present-day use, the term refers to lawful hunting, as distinguished from poaching, which is the killing, trapping or capture of the hunted species contrary to applicable law...

 in season.

History

The Gates of the Rocky Mountains were named by Lewis and Clark. Captain Lewis wrote on July 19, 1805,

Geology

The prominent gray cliffs along the Missouri River

Missouri River

The Missouri River flows through the central United States, and is a tributary of the Mississippi River. It is the longest river in North America and drains the third largest area, though only the thirteenth largest by discharge. The Missouri's watershed encompasses most of the American Great...

 in the Gates of the Mountains are formed by Madison Limestone

Madison Limestone

The Madison Limestone is a thick sequence of mostly carbonate rocks of Mississippian age in the Rocky Mountain and Great Plains areas of western United States. The rocks serve as an important aquifer as well as an oil reservoir in places...

. At the southern entrance to the canyon the trace of the Eldorado thrust fault

Thrust fault

A thrust fault is a type of fault, or break in the Earth's crust across which there has been relative movement, in which rocks of lower stratigraphic position are pushed up and over higher strata. They are often recognized because they place older rocks above younger...

 juxtaposes Proterozoic

Proterozoic

The Proterozoic is a geological eon representing a period before the first abundant complex life on Earth. The name Proterozoic comes from the Greek "earlier life"...

 Belt Supergroup

Belt Supergroup

The Belt Supergroup, is an assemblage of Mesoproterozoic sedimentary rocks which outcrop chiefly in western Montana, but also exposed in Idaho, Washington, Wyoming, and British Columbia. It is most famous as the formation that makes up Glacier National Park in northwest Montana...

 Greyson Shale over much younger Madison Limestone; this faulting was part of the Sevier orogeny

Sevier orogeny

The Sevier orogeny was a mountain-building event that affected western North America from Canada to the north to Mexico to the south. This orogeny was the result of convergent boundary tectonic activity between approximately 140 million years ago and 50 Ma. The Sevier River area of central Utah...

. Within the canyon, caves and folded layers of Madison Limestone are found. Near the north end of the canyon, at Mann Gulch

Mann Gulch

Mann Gulch is a gulch in the Gates of the Mountains Wilderness of the upper Missouri River, north-northeast of Helena, Montana, in southeastern Lewis and Clark County. It is on the east side of the Missouri River and approximately east of Interstate 15 , between Helena and Wolf Creek...

 and further north, alternating ridges and valleys reflect the alternating resistance of younger rock layers overlying the Madison Limestone. The entire canyon is an example of a superposed or antecedent stream

Entrenched river

An entrenched river is a river that is confined to a canyon or gorge, usually with a relatively narrow width and little or no flood plain, and often with meanders worn into the landscape...

, in which the river pre-dates the uplift of the rocks and kept pace with erosion as uplift occurred.