Colonial history of the United States 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. In 1763, Louisiana was ceded to Spain around New Orleans and west of the Mississippi River. In the 1780s, the western border of the newly independent United States stretched to the Mississippi River. The United States reached an agreement with Spain for
Convention of 1800 This led to the Quasi-War of 1798–1800; largely dismantled after independence, the US Navy was quickly re-established and gained the upper hand, with limited support from the British Royal Navy. Despite this, President John Adams continued to seek a diplomatic solution; in addition to the cost of the Quasi-War, the US was increasingly concerned by French ambitions in North America. France ceded Louisiana-New Spain to Spain by the 1763 Treaty of Paris; combined with Spanish Florida, Spain controlled the Mississippi River basin (see Map), effectively blocking US expansion to the South and West. Efforts to manage this through diplomacy, including