The first Fort Lewis army post was constructed in Pagosa Springs, Colorado, in 1878, and was relocated in 1880 to Hesperus, Colorado, on the southern slopes of the La Plata Mountains. In 1891, Fort Lewis was decommissioned and converted into a federal, off-reservation boarding school.
In 1911, the fort's property and buildings in Hesperus were transferred to the state of Colorado to establish an "agricultural and mechanic arts high school." That deed came with two conditions: that the land would be used for an educational institution, and was “to be maintained as an institution of learning to which Indian students will be admitted free of tuition and on an equality with white students” in perpetuity (Act of 61st Congress, 1911). Both conditions have been the Fort Lewis school's missions and guides over the past century.
In the 1930s, the Fort Lewis high school expanded into a two-year college, and in 1948 became Fort Lewis A&M College, under control of State Board of Agriculture. The "Aggies" studying at the Fort Lewis Branch of the Colorado State College of Agriculture & Mechanics could chose from courses including agriculture, forestry, engineering, veterinary science, and home economics.
Fort Lewis underwent another period of growth and changes starting in 1956, when the college moved from its long-time home in Hesperus to its present location, 18 miles east, atop what was then known as Reservoir Hill, overlooking Durango. Here, Fort Lewis College became a four-year institution, awarding its first baccalaureate degrees in 1964.
Also in 1964, the college separated from the State Board of Agriculture and dropped the "A&M" moniker. At that time, the new Fort Lewis College also changed its mascot from "Aggies" to the "Raiders," and changed the school's colors from the green and yellow of the Colorado State University system it had been affiliated with to the blue and gold it still sports today. In 1994, the college's mascot became the Skyhawks, retaining the blue and gold.
In 1995, Fort Lewis College joined the Council of Public Liberal Arts Colleges, and in 2002, the College became independent of the Colorado State University system, and formed its own governing Board of Trustees. In 2005, the Colorado state legislature raised the college's admission standards, making it a "selective" college.