Long Tieng (also spelled Long Chieng, Long Cheng, or Long Chen) is a Laotian military base located in Xiangkhouang Province.During the Laotian Civil War, it served as a town and airbase operated by the Central Intelligence Agency of the United States.During this time, it was also referred to as Lima Site 98 (LS 98) or Lima Site 20A (LS 20A).
At the height of its significance in the late 1960s, the "secret city" of Long Tieng maintained a population of 40,000 inhabitants, making it the second largest city in Laos at the time, although it never appeared on maps throughout this period.
In 1962 the CIA first set up a headquarters for Major General Vang Pao in the Long Tieng valley, which at that time had almost no inhabitants. By 1964 a 1260m-long runway had been completed and by 1966 Long Cheng was one of the largest US installations on foreign soil, becoming one of the busiest airports in the world.
In 1971 a US Air Force F-4D Phantom mistakenly hit Long Tieng with cluster bombs, causing a fire that destroyed the CIA operations shack.
North Vietnamese forces began to threaten Long Tieng in late 1971, and came close enough to start shelling the area on December 31 at 15:30 local time. In early January, 19,000 North Vietnamese forces launched a four pronged attack on Long Tieng from all four cardinal directions, encircling the site, capturing several facilities and positions, and installing antiaircraft batteries. Despite subsequent claims of victory from communist forces, the 10,000 defenders of Long Tieng, a mixture of Hmong, Thai, and Lao, had not been overrun, and in mid-month reinforcements appeared in the form of CIA-led Thais and 1200 elite irregulars from southern Laos. After enduring a third to 50% casualties, these forces succeeded in taking back key positions by the end of the month.
Long Tieng was often described as “The Most Secret Place on Earth”. It was located in a valley at 3,100 feet elevation, high enough to have chilly nights and cold fogs. It was surrounded by mountains and on the northwest side of the runway were karst outcrops several hundred feet high. In the shadow of the Karst outcrops was “Sky” the CIA headquarters in Long Tieng. Jerry Daniels, a CIA officer codenamed “Hog,” is said to have named Sky after his home state of Montana, known as “Big Sky Country.”Long Tieng was protected on three sides by limestone mountains.
“What a place is Long Tieng,” said USAID officer Jim Schill. “Tribal soldiers dressed in military garb standing next to traditionally dressed Hmong, with Thai mercenaries milling about. And the Americans here are mostly CIA operatives with goofy code names like Hog, Mr. Clean, and Junkyard. The town itself is not much. There’s one paved road running through it and tin shacks on either side with eating shops, food stalls, and living quarters.”
During the Secret War, Long Tieng became the largest Hmong settlement in the world. Anne Fadiman, said that Long Tieng "became a desultory metropolis, an unpaved, sewerless city of 30,000 where Hmong ran noodle stands, cobbled shoes, tailored clothes, repaired radios, ran military-jeep taxi services, and interpreted for American pilots and relief workers."
On February 22, 1975, the final defensive outpost for Long Tieng was defeated, leading US Brigadier General Heinie Aderholt to begin planning an evacuation. By May 1975, there were almost 50,000 guerillas and refugees living in and around the city. However, by then, the U.S. had withdrawn all its civilian and military personnel from Indochina, except for a few Embassy personnel in Laos and Jerry Daniels in Long Tieng. There were few resources for an evacuation. Daniels had only a single transport aircraft and Hmong pilot in Long Tieng to take evacuees to Udon Thani, Thailand. Aderholt located three additional American transport aircraft and pilots in Thailand. He had the planes “sheep dipped” to remove all markings identifying them as American-owned and sent them to Long Tieng. On May 10, 1975, the Vang Pao reluctantly followed the CIA's counsel and decided that he could no longer maintain Long Tieng against the opposing forces. Between May 10 to May 14, 1975, US C-130s and C-46s airlifted people from the airbase to US bases in Thailand. Between 1,000 and 3,000 Hmong were evacuated. Crowds of civilians surrounded the flights on the runways, creating a chaotic atmosphere. Those evacuated were primarily Hmong military leaders and CIA employees. The evacuation ended with the departure of Major General Vang Pao and Jerry Daniels. Vang Pao told the people still on the tarmac "Farewell, my brothers, I can do nothing more for you, I would only be a torment for you," as he boarded a helicopter. Tens of thousands of fighters and refugees were left behind. The over 10,000 Hmong on the airfield expected more aircraft to return, but they later learned that there were no more aircraft. The shelling of Long Tieng began on the afternoon of May 14. Many of the Hmong fighters and their families made their way overland to Thailand during the next several years, a dangerous journey that cost many of them their lives.