French claims to French Louisiana stretched thousands of miles from modern Louisiana north to the largely unexplored Midwest, and west to the Rocky Mountains. It was generally divided into Upper and Lower Louisiana. This vast tract was first settled at Mobile and Biloxi around 1700, and continued to grow when 7,000 French immigrants founded New Orleans in 1718. Settlement proceeded very slowly; New Orleans became an important port as the gateway to the Mississippi River, but there was little other economic development because the city lacked a prosperous hinterland.