Illinois River is a tributary of the Michigan River

Michigan River

The Michigan River is a tributary of the North Platte River, approximately long, in north central Colorado in the United States. It drains a rural part of the eastern side of North Park in eastern Jackson County. The river issues from Michigan Lakes, a chain of alpine lakes at , along the...

, approximately 71 miles (114.3 km) long, in Jackson County

Jackson County, Colorado

Jackson County is the fourth-least densely populated of the Colorado 64 counties of the U.S. state of Colorado. The county population was 1,577 at the 2000 Census. The county seat and the only municipality in the county is the Town of Walden.- History :...

 in north central 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...

. It drains part of the North Park

North Park (Colorado basin)

North Park is a high, sparsely populated basin in the Rocky Mountains in north central Colorado in the United States. It encompasses a wide valley in Jackson County rimmed by mountain ranges at the headwaters of the North Platte River and several smaller tributaries, including the Michigan River,...

 basin south of Walden

Walden, Colorado

The Town of Walden is a Statutory Town that is the county seat of, and the only incorporated municipality in, Jackson County, Colorado, United States. It is situated in the center of a large open valley called North Park. People from Walden and the surrounding area refer to themselves as "North...

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The Illinois River starts in the Never Summer Mountains

Never Summer Mountains

The Never Summer Mountains are a mountain range in the Rocky Mountains in north central Colorado in the United States. The range is located along the northwest border of Rocky Mountain National Park, forming the continental divide between the headwaters of the Colorado River in Rocky Mountain...

 near the continental divide

Continental divide

A continental divide is a drainage divide on a continent such that the drainage basin on one side of the divide feeds into one ocean or sea, and the basin on the other side either feeds into a different ocean or sea, or else is endorheic, not connected to the open sea...

, just south of Farview Mountain. It descends northward through a winding gorge, emerging into North Park at approximately 8000 feet (2,438.4 m) above sea level. It flows northward through the valley as a winding stream, past Rand

Rand, Colorado

Rand is an unincorporated town and a U.S. Post Office established in 1881 in Jackson County, Colorado. It is a ranching community at the southern end of North Park south of Walden consisting of several homes and businesses, a post office, and ranching facilities...

. It passes under State Highway 14

Colorado State Highway 14

State Highway 14 in the U.S. state of Colorado is an east–west state highway approximately long. One of the longest state highways in Colorado, it traverses four counties along the northern edge of the state, spanning a geography from the continental divide in the Rocky Mountains to the...

 just southeast of Walden

Walden, Colorado

The Town of Walden is a Statutory Town that is the county seat of, and the only incorporated municipality in, Jackson County, Colorado, United States. It is situated in the center of a large open valley called North Park. People from Walden and the surrounding area refer to themselves as "North...

 and joins the Michigan from the north just north of Walden. A portion of the valley of the river south of Walden is located within the Arapaho National Wildlife Refuge

Arapaho National Wildlife Refuge

The Arapaho National Wildlife Refuge is a United States National Wildlife Refuge located in north central Colorado. The refuge is located in North Park in central Jackson County south of the town of Walden. The refuge was established in 1967 to furnish waterfowl with a suitable place to nest and...

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