The Golden Triangle is a large, mountainous region of approximately 200,000 km² in northeastern Myanmar, northwestern Thailand and northern Laos, centered on the confluence of the Ruak and Mekong rivers. The name "Golden Triangle" was coined by Marshall Green, a U.S. State Department official, in 1971 in a press conference on the opium tradeā¦The Golden Triangle is a large, mountainous region of approximately 200,000 km² in northeastern Myanmar, northwestern Thailand and northern Laos, centered on the confluence of the Ruak and Mekong rivers. The name "Golden Triangle" was coined by Marshall Green, a U.S. State Department official, in 1971 in a press conference on the opium trade. Today, the Thai side of the river confluence, Sop Ruak, has become a tourist attraction, with the House of Opium Museum, a Hall of Opium, and a Golden Triangle Park, and no opium cultivation.