The agreement enabling the base's existence, from 1941 until closure in 1966, enabled it to function as a de facto enclave of United States territory within, first the Dominion of Newfoundland and later Canada, making United States military personnel stationed at the base subject to the Uniform Code of Military Justice.

March 3, 1960, while returning home from his army stint, Elvis Presley landed on Ernest Harmon Air Force Base for a refueling en route from Frankfurt, Germany and Glasgow Prestwick Airport, Prestwick, Scotland to McGuire Airforce Base in Fort Dix, New Jersey, US.

During 1940, Germany was threatening the majority of Europe, as well as North America, through its successful air, land and sea campaigns.

The destructiveness of the Luftwaffe and Kriegsmarine in the Battle of Britain and Battle of the Atlantic alarmed military planners in the United States who theorized that the Nazis could in future establish a beachhead on Newfoundland and the adjacent French islands of Saint Pierre and Miquelon and use it for launching air attacks and eventually land and sea attacks on the industrial heartland of North America.

The 76th Congress approved the 99-year lease and in April 1941, construction began on a deepwater port and adjacent air field.

It was called Battery T8503 and was operated by Coast Artillery Corps troops of the Harbor Defenses of Argentia and St.

In April 1957, with the rising threat of nuclear war, the Strategic Air Command (SAC) assumed control of the base for use as a forward refuelling point.

In 1953, the 347th (Engineer Aviation) battalion was assigned the immense task (along with 2,502 contractor personnel) of completing the 62 line construction projects at Ernest Harmon AFB.

The machinery which constructed the bypass road was buried at the end of the property when it became over used and obsolete in 1959–1960, under the supervision of Warrant Officer Ebb Higdon, Company A.

In 1986, when this information was made available to the town of Stephenville via a series of articles in the Georgian newspaper, several doubters and curiosity seekers, armed with metal detectors, swarmed over the site and located the buried equipment.

It was necessary to begin construction of the road at Cormiers Village and work back towards Stephenville pending the finalizing of property agreements.

Jones and was responsible for the construction of 200 on base houses, two seven-story barracks for 1,500 airmen, additional runways and the Central Heating (steam) Plant.

The first educational institution at Ernest Harmon AFB was an elementary school established in 1948 using a small clap-board building that housed 28 children and 3 teachers.

Stephenville Air Base and later Ernest Harmon AFB were located in the protection of the Long Range Mountains and harbour of the St. Georges Bay area, virtually cut off from rest of the island, except for a few roads and boat and plane traffic.

But during the 1940s and 1950s, when roads were virtually non-existent and surface travel was limited to the slow narrow-gauge passenger trains of the Newfoundland Railway which linked to small coastal steamships or ferries to the mainland at North Sydney, Nova Scotia.

In addition to USAAF/USAF aircraft, the only other option for travel was the railway and ferries/coasters, or exploring the limited local road network which stretched along the coast and into the uninhabited interior of the island.

Corner Brook was the major population centre for the region, given its industrial base, harbour, and nearby recreational opportunities in the Humber Valley.

The village of Stephenville grew from a hamlet of several hundred people with no paved streets, side walks, water or sewage system in 1941 into a modern town of over 5,000 by the mid-1950s.

By the time Ernest Harmon AFB closed in the mid-1960s, the town had more than doubled in size, partly as a result of the provincial government's forced resettlement policy toward residents of outports.

Sports facilities and groups were set for softball, baseball, bowling, golf, picnicking, archery and guns.

Given its size and importance, and the large number of personnel assigned during the height of the Cold War in the 1950s, the base managed to attract many celebrities to visit and/or perform, including Marilyn Monroe, Elvis Presley, Frank Sinatra and Bob Hope.