Lanzhou is the capital and largest city of Gansu Province in Northwest China.The prefecture-level city, located on the banks of the Yellow River, is a key regional transportation hub, connecting areas further west by rail to the eastern half of the country. Historically, it has been a major link on the Northern Silk Road and it stands to become a major hub on the New Eurasian Land Bridge. The city is also a center for heavy industry and petrochemical industry.
Lanzhou is home to 3,616,163 inhabitants at the 2010 census and 2,177,130 in the built-up area (urban) of 1,088 square kilometres (420 sq mi). By 2018, its population within the central urban area of 298 square kilometres (115 sq mi) rose to 2,890,000 people.
Covering an area of 1631.6 square kilometers (629.96 square miles), it was once a key point on the ancient Silk Road. Today, it is a hub of the Silk Road Tourism Ring, with Maiji Caves to the east, Bingling Temple Grottoes to the west, Labrang Monastery to the south and Dunhuang Mogao Caves to the north.