New Orleans, Louisiana, on September 17th 2000. North is at top. New Orleans (centre) is a port city in Louisiana, USA, on the coast of the Gulf of Mexico. The lake to the north of the city is Lake Pontchartrain, one of the largest salt-water lakes in the USA. The brown colour of its water results from a high sediment load. The Mississipi River runs from east to south through the city towards its mouth (not seen). New Orleans suffered extensive damage during Hurricane Katrina in August 2005.