Lanchow (lán zhōu 兰州) is the capital and largest city of Gansu Province in Northwest China. A prefecture-level city, it is a key regional transportation hub, allowing areas further west to maintain railroad connections to the eastern half of the country. 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 kilometers.