Levees and natural bluffs have protected most of Memphis from serious flooding, but those living in the affluent neighborhood of Mud Island were struggling to keep the waters at bay.
The floodwater has already engulfed homes along the shoreline and on Monday broke through a sandbag barrier set up around a condominium on the other side of the road.
The Memphis music landmarks of Graceland and Sun Studios on Beale Street have not been affected.
Portions of the Mississippi were closed to shipping and the US Coast Guard opened flood gates outside of New Orleans to help protect the low-lying city as a flood wave makes its way slowly down to the Gulf of Mexico.
Heavy rains last month filled rivers and creeks already swollen from the melting of a thick winter snow pack, which are now backing up because the Mississippi is so swollen.
It's the biggest flood in the Mississippi Valley since 1937 and the river is rising above those records in some areas.
Meanwhile, Governor Steve Beshear of Kentucky said Monday most of the 3,800 people evacuated from counties along the Ohio and Mississippi rivers may soon be allowed to return home and assess the damage. US President Barack Obama meanwhile declared a "major disaster" in both Missouri and Tennessee on Monday, ordering federal aid to supplement local