Nearly 240,000 people still had no electricity in Louisiana on Monday, due to Hurricane Isaac last week.
More than 11,000 were also without power in Mississippi and about 5,000 were without power in Arkansas.
Isaac hit New Orleans on Wednesday, seven years to the day that Hurricane Katrina flooded the city on 29 August, 2005.
Seven people - five in New Orleans and two in Mississippi - were killed as a result of the storm. The BBC reports over 3500 people were still in shelters on Sunday.
President Barack Obama arrived in New Orleans on Monday with Louisiana Governor Bobby Jindal and Mayor Mitch Landrieu, before going to visit storm damage in St John the Baptist Parish.
Republican presidential candidate Mitt Romney toured damaged areas in Louisiana on Friday.
At the height of the storm, about 850,000 people were reported to have lost power in Louisiana, Mississippi, Alabama, Texas and Arkansas.