The North Fork Gunnison River (locally known as the North Fork) is a tributary of the Gunnison River

Gunnison River

The Gunnison River is a tributary of the Colorado River, long, in the Southwest state of Colorado. It is the fifth largest tributary of the Colorado River, with a mean flow of 4320 ft³/s .-Description:...

, 33.5 miles (53.9 km) long, in southwestern Colorado

Colorado

Colorado is a U.S. state that encompasses much of the Rocky Mountains as well as the northeastern portion of the Colorado Plateau and the western edge of the Great Plains...

 in the United States

United States

The United States of America is a federal constitutional republic comprising fifty states and a federal district...

. It drains part of the southwestern flank of the Elk Mountains

Elk Mountains (Colorado)

The Elk Mountains are a high, rugged mountain range in the Rocky Mountains of west-central Colorado in the United States. The mountains sit on the western side of the Continental Divide, largely in southern Pitkin and northern Gunnison counties, in the area southwest of Aspen, south of the Roaring...

 northeast of Delta

Delta, Colorado

The City of Delta is the county seat and the most populous city of Delta County, Colorado, United States. The population was 8,915 at the 2010 census...

.

It is formed in the mountains of northwestern Gunnison County

Gunnison County, Colorado

Gunnison County is the fifth most extensive of the 64 counties of the state of Colorado in the United States. The county population was 15,324 at the 2010 census. The county was named for John W. Gunnison, a United States Army officer and captain in the Army Topographical Engineers, who surveyed...

 by the confluence of Muddy Creek and Anthracite Creek. The confluence is located along State Highway 133

Colorado State Highway 133

State Highway 133 is a long north–south byway connecting State Highway 82 to the north and State Highway 92 to the south, and travels through the towns of Hotchkiss, Somerset, Redstone, and Carbondale. Highway 133 travels over a significant mountain pass on the northern end, called McClure Pass,...

 on the south side of McClure Pass

McClure Pass

McClure Pass is a high mountain pass in the Rocky Mountains of western Colorado in the United States.- Overview :...

. It descends to the southwestern through a widening valley past Somerset

Somerset, Colorado

Somerset is an unincorporated mining town town and a U.S. Post Office located in Gunnison County, Colorado, United States. The Somerset Post Office has the ZIP Code 81434.- Geography :Somerset is located at ....

, Paonia

Paonia, Colorado

The Town of Paonia is a Statutory Town in Delta County, Colorado, United States. The population was 1,497 at the 2000 census.-History:The area was first explored in 1853 by Captain John W. Gunnison of the United States Army...

, and Hotchkiss

Hotchkiss, Colorado

Hotchkiss is a Statutory Town in Delta County, Colorado, United States. The population was 968 at the 2000 census.-Geography:Hotchkiss is located at ....

. It joins the Gunnison in eastern Delta County

Delta County, Colorado

Delta County is the 17th most populous of the 64 counties of the State of Colorado of the United States. The county population was 27,834 in the 2000 U.S. Census. The county seat is the City of Delta...

 downstream from the Black Canyon

Black Canyon of the Gunnison National Park

thumb|upright|Black Canyon of the GunnisonBlack Canyon of the Gunnison National Park is a United States National Park located in western Colorado, and managed by the National Park Service...

 between Delta and Hotchkiss. The valley of the river, called the North Fork Valley, has a temperate climate that has historically been a center of fruit

Fruit

In broad terms, a fruit is a structure of a plant that contains its seeds.The term has different meanings dependent on context. In non-technical usage, such as food preparation, fruit normally means the fleshy seed-associated structures of certain plants that are sweet and edible in the raw state,...

 growing in southwestern Colorado. It is also a regional center of the coal

Coal

Coal is a combustible black or brownish-black sedimentary rock usually occurring in rock strata in layers or veins called coal beds or coal seams. The harder forms, such as anthracite coal, can be regarded as metamorphic rock because of later exposure to elevated temperature and pressure...

 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...

 industry, centered around the mining town of Somerset in the upper valley. Modern coal mining operations are highly visible along the upper valley walls. The creeks at the headwaters of the river pass through areas of highly erodible shale

Shale

Shale is a fine-grained, clastic sedimentary rock composed of mud that is a mix of flakes of clay minerals and tiny fragments of other minerals, especially quartz and calcite. The ratio of clay to other minerals is variable. Shale is characterized by breaks along thin laminae or parallel layering...

, resulting in high concentrations of sediment during springtime runoff.