Yongchang County (永昌县) is a county located in the province of Gansu in China. It belongs to the prefecture of Jinchang. The ancient North Silk Road passes through Yongchang County; numerous Han envoys were sent west along this trackway, some parties exceeding 100 members late in the first millennium BC. The Han Dynasty sent one mission to Parthia, which was reciprocated at around 100 BC: Roman emissaries were captured by the Chinese in 30 BC along the Silk Road at Yongchang.