The camp was established in 1942 as Big Delta Army Air Field. During World War II, The Alaska Highway was built to connect an existing road in Dawson Creek, British Columbia, Canada with the Richardson Highway in Alaska, a distance of 1423 miles (2290 km). The Alaska Highway met the Richardson Highway at Delta Junction, 5 miles (8 km) north on the Richardson Highway from what is now Fort Greely. The United States used the base to aid Russia against Germany and Japan by sending airplanes and supplies authorized by the Lend-lease act through Alaska and into the Russian Far East. The name was later changed to Allen Army Airfield. After World War II, Fort Greely was built south of the air field.

After World War II, the War Department decided that the American Soldier must be able to live and operate in any degree of cold. This decision was based on experience gained in combat and predictions of future possibilities for international obligations. A group of task forces was therefore organized to test U.S. Army equipment in the cold. Task Force Frigid and Task Force Williwaw were dispatched to Alaska during the winters of 1946 and ‘47.

The information and data collected by task force personnel was a beginning, but it took time for men to be transported, to set up quarters for a short period of actual testing, and then pack up and leave until the next year. The expense of moving in and out was taken into consideration when the final reports were filed. When questions arose concerning the reports, there was no one available to answer them, for the task forces had been disbanded, and the personnel returned to their home units. The major shortcomings of these task forces included having insufficient time to establish units on test sites, lack of acclimatization period for both personnel and equipment, and a lack of continuity. Based on these results, it was recommended that a permanent test organization be established, with test groups representing each of the "Army Field Force Boards" located in the "Zone of the Interior."

In 1949, the Department of the Army ordered the organization of the Arctic Test Branch at Big Delta Air Force Base, Alaska (now known as Fort Greely). A cadre for the organization was activated at Fort Knox, Kentucky, in March 1949, by the transfer of personnel from each of the "Army Field Force Boards." The organization moved to Alaska in July of 1949 and test operations were initiated. Shortly thereafter, the organization name was changed to the Arctic Training Center. In 1957, it was renamed the U.S. Army Arctic Test Board, with the mission of conducting Arctic service tests of all Army field equipment.

From 1955, Fort Greely and a huge tract of land around it (withdrawn from the Department of the Interior) were used for training soldiers for cold weather combat during the Cold War with the former Soviet Union.

In August of 1962, as a result of the reorganization of the Army, the Arctic Test Board was established as a Class II activity and placed under the command of the U.S. Army Test and Evaluation Command (TECOM). The Board was later renamed the Arctic Test Center and expanded to absorb the Research and Development Office, Alaska, the Technical Services Test Activity, and the General Equipment Test Branch, all located at Fort Wainwright, Alaska, and the Chemical Corps Test Activity at Fort Greely.

In the 1980s, when the Cold War ended with the collapse of the Soviet Union, Fort Greely was gradually realigned through a gradual draw-down in the numbers of soldiers.

In 1995, Fort Greely was selected for realignment (but not closure) as a cost-saving measure. Only the Cold Regions Test Center (CRTC) and Public Works functions were to remain on the installation. Large portions of the post were to be closed and, at one point, the main post was to be turned over to the city of Delta Junction for use as a private prison. Ultimately, plans for the prison fell through. In 2001, headquarters for the Northern Warfare Training Center and Cold Regions Test Center were moved to nearby Fort Wainwright. Training ranges were also transferred to Fort Wainwright control and renamed Donnelly Training Area. Though its command moved, CRTC continued operating from Fort Greely. The Northern Warfare Training Center also continued operations at Black Rapids Training Facility.

After the United states announced that it would withdraw from the Anti-Ballistic Missile Treaty, Fort Greely was selected as a site for the Ground-Based Midcourse Defense system. Starting in the summer of 2002, the United States government began work on the missile defense installation at Fort Greely, planning to deploy a total of 25 to 30 anti-ballistic missiles by 2010. Concurrently, the Missile Defense Command took command of Fort Greely, relinquishing direct Army control, while the Army retained control of the nearby Donnelly Training Area.

Fort Greely is a launch site for anti-ballistic missiles and home of the Cold Regions Test Center (CRTC), as Fort Greely is one of the coldest areas in Alaska, and can accommodate cold, extreme cold, or temperate weather tests depending on the season.

Testing efforts are centered at the Bolio Lake Range Complex, approximately 10 miles south of Fort Greely. Arkansas Range is the main test site for mines and small arms. Washington Range is a multi-purpose range used for air defense missile firings, artillery tests, such as Sense and Destroy Armor (SADARM), and smoke and obscurant tests requiring large areas and mobility testing. Texas Range is available for direct-fire tests, as well as sensor, small arms, and missile tests. Oklahoma Range, primarily used for indirect-fire work, is capable of observed fire to 30km and unobserved fire to 50km.

As it is not near the ocean, this area is drier than coastal Alaska and experiences seasonal extremes typical of subarctic areas. The annual precipitation is only 12 inches (305 mm), including 37 inches (94 cm) of snow. The average low temperature in January is −11 °F (−23 °C). The average high during July is +69 °F (+20 °C). Temperature extremes have been recorded from −63 °F to +92 °F (−53 °C to +33 °C).

Fort Greely is mostly sunny in the summer and split between clear and overcast days in the winter. On clear winter nights, the aurora borealis can often be seen dancing in the sky. Like all sub arctic regions, the months from May to July in the summer have no night, only twilight during the night hours. The months of November to January have little daylight.

 Fort Greely is approximately 100 Miles s/e of Fairbanks, or 350 Miles n/e of Anchorage. Fort Greely is located in a picturesque state with an abundance of mountains, lakes, rivers, glaciers and wildlife. The post is surrounded by two mountain ranges - the Granites and the Alaska Range - providing a beautiful view of snow-capped mountains (for many in government quarters this can be seen by merely glancing out the window).

Located at the foot of the Alaska Range, Fort Greely enjoys not only an incredible view of the surrounding scenery but also, excellent hunting and fishing opportunities. The vast terrain offers additional recreational activities such as cross-country skiing, snow machining and boating. Indeed, many of Alaska's best outdoor adventures begin here. In fact, approximately 640,000 acres of wilderness encompass the testing/bombing ranges. Over a million square feet of prime industrial, light industrial and commercial property is available for privatization. Land can be procured for new development and property may be conveyed/leased at less than fair market value. With no local taxes, area businesses have a distinct competitive business advantage. Located near two major highways, the Richardson and the Alcan Highways, the primary north/south transportation corridor through the state, Fort Greely is approximately 5 miles south of Delta Junction.