The Longmen Mountains, also tautologically referred to in English-language publications as the Longmenshan Mountains, are a mountain range in Sichuan province in southwestern China. The range runs in a roughly northeast to southwest direction, roughly from Guangyuan near the province's northeastern border, to the western part of the Chengd…The Longmen Mountains, also tautologically referred to in English-language publications as the Longmenshan Mountains, are a mountain range in Sichuan province in southwestern China. The range runs in a roughly northeast to southwest direction, roughly from Guangyuan near the province's northeastern border, to the western part of the Chengdu Prefecture, in the central part of the province, where it approaches the southern end of the Qionglai Range. The Longmen Mountains form the northwestern rim of the Sichuan basin.