Jackson County is the fourth-least densely populated of the 64 counties of the state of Colorado. As of the 2010 census, the population was 1,394, making it the fourth-least populated county in Colorado. The county seat and only incorporated municipality in the county is the Walden.
Most of Jackson County is a high relatively broad intermontane basin known as North Park, which covers . This basin opens north into Wyoming and is rimmed on the west by the Park Range, on the south by the Rabbit Ears Range and the Never Summer Mountains, and on the east by the Medicine Bow Mountains. Elevations range from 7,800 to above sea level and is home to the head waters of the North Platte River. The term park is derived from parc, the French word for game preserve. At one time North Park was filled with herds of deer, antelope and buffalo. There were so many buffalo in the area the Ute Tribe gave North Park the name "Bull Pen." Now deer, elk, and cattle vie for the same area.
In November 1861, Colorado set up 17 counties for the state, including Larimer County. This was where Jackson County would be carved out of in 1909. Before then, both Grand and Larimer Counties claimed the North Park area. In the beginning, no one paid much attention to North Park because it was hunting grounds of the Ute and Arapaho Indians. They fiercely defended these lands and the white settlers were often afraid to venture in. When valuable minerals were discovered in North Park, Grand County claimed it as part of their county because they wanted the revenue it would provide. The residents didn't care much because the county seat for Grand County was closer than the one in Larimer County, and all official business needed to be done at the county seat. But Larimer also claimed this county and it was contested all the way to the Colorado Supreme Court. In 1886 the court decided in favor of Larimer. This did not make the North Park residents very happy and they pushed for their own county until Jackson was formed.