Longmen is a town in Fuyang District, Hangzhou, in northwestern Zhejiang province, People's Republic of China. It has a population of about 7,000 and lies 17 kilometres (11 mi) south of the centre of Fuyang District. The town is situated south of the Fuchun River, at the foothills of the Xianxia Range, and it oversees 11 administrative villages.
One of Longmen's most distinctive characteristics is the composition of its population: over 90% of its residents share the surname Sun. This unusually concentrated surname pattern is the town's best-known feature.