The closure at Natchez was the third in a series of recent moves designed to protect homes and businesses behind levees and floodwalls along the river.
Over the weekend, the Army Corps opened the Morganza Spillway, choosing to flood rural areas with fewer homes to protect Baton Rouge and New Orleans. Another spillway near New Orleans was opened earlier, but it did not threaten homes.
The Mississippi Emergency Management Agency said there are more than 4,800 people displaced in Mississippi due to flooding, with more than 2,000 of them in Vicksburg and surrounding areas in Warren County. MEMA Spokesman Jeff Rent said more than 6,000 people in Mississippi could be displaced before the flood is over.
Warren County Sherriff Martin Pace said deputies continue to use boats to patrol neighborhoods.
"It's been good so far. We've had no major problems," Pace said. "So far, so good. We just need this water to get out of here."
Sayre reported from New Orleans. Associated Press writers Brian Schwaner in New Orleans; Scott Mayerowitz in New York, Christopher Leonard in St. Louis and Sheila Byrd in Jackson contributed to this report.
Copyright 2011 The Associated Press.