Hengduan Mountains
Yanyuan County (; ) is a county in Liangshan Prefecture, Sichuan Province, China, bordering Yunnan province to the west. The county is located in Sichuan's rugged Hengduan Mountains in southwest Sichuan, but the county seat of () is situated in an unusually flat basin with a diameter. Yanjing, as the county seat, is usually referred to as Yanyuan.