The death toll from Ike rose to 30 people in eight states extending from the hurricane-pounded Gulf Coast to the storm-battered Midwest.
Illinois officials said they planned to ask Gov. Rod Blagojevich to issue a disaster declaration for both the city of Chicago and Cook County, a move that would make additional funds available to deal with flood-related costs.
Cook County was placed under a state of emergency as thigh-high water prompted dozens of boat rescues in Chicago.
No deaths were reported Sunday in Illinois, but elsewhere in the Midwest the remnants of Ike proved deadly.
Six people died in floodwaters and high winds in Indiana, the state's Department of Homeland Security said Monday. Among them were a teacher and his father, who were sucked into a culvert and drowned Sunday morning while trying to rescue a 10-year-old boy from a flooded ditch in Chesterton in northwest Indiana, the state officials said. Falling trees were blamed for three deaths in southern Indiana. Another death in the southern part of the state was wind-related, officials said.
"We've never had flooding like this," said Tom DeGiulio, town manager in Munster, Ind. About 40 Indiana National Guard troops were activated Sunday to assist with the evacuation of up to 5,000 residents there.
Three people died in Missouri, including a 21-year-old woman who was likely swept away by rising floodwaters while trying to help another man, authorities said. Two died in the St. Louis area - a woman struck by a tree limb and an elderly man found dead in a home's flooded backyard. Authorities suspect the man drowned.
Strongs winds were blamed for three deaths in Ohio. Two motorcyclists were killed when a tree toppled onto them at a state park in southwest Ohio, said state Department of Natural Resources spokesman Jason Fallon, and a woman was killed when a tree crashed into her home in Hamilton County, just north of Cincinnati.
In Tennessee, two men sitting in a golf cart on the 16th hole of a Nashville golf course were killed when a tree fell over on them Sunday morning, fire department spokesman Ricky Taylor said.
One death was reported in Arkansas, where a 29-year-old man was killed when a tree fell on a mobile home as he was preparing to leave, authorities said.
The remnants of Ike dumped as much as 6 to 8 inches of rain in parts of Indiana, Illinois and Missouri, spawned a tornado Arkansas that damaged several buildings, and delivered hurricane-force winds to Ohio, forcing Cincinnati's main airport to temporarily shut down. Flooding in Missouri closed the street in front of St. Louis' famed Gateway Arch.
Power outages darkened more than a million homes and businesses in Ohio and Kentucky.
More than 680,000 Duke Energy customers were without power Sunday night in southwest Ohio and northern Kentucky in the biggest outage in the company's history, said Duke Energy spokeswoman Kathy Meinke.
"It's going to be quite extensive," Meinke said. "Over 90 percent of our customers are without service."
More than 354,000 customers were without power in central Ohio, said American Electric Power spokesman Jeff Rennie. About 310,000 Ohio Edison customers were in the dark in northeast Ohio, said spokeswoman Robin Patton.
In Chicago, Saturday's rainfall of 6.64 inches at O'Hare International Airport set a record for a single day. The previous record was 6.49 inches, recorded on Aug. 14, 1987.
In Missouri, winds as high as 60 mph and torrential rains of up to 7 inches raised new concerns about swelling rivers. Major flooding was expected along the Mississippi from Ste. Genevieve to Cape Girardeau by late this week, the National Weather Service said.
Strong winds prompted the Cincinnati/Northern Kentucky International Airport to evacuate its control tower and cancel about 40 flights before resuming air traffic, airport spokesman Ted Bushelman said.
Strong gusts ripped off part of the roof from a Delta Airlines hangar and damaged another airport building, Bushelman said. He said winds were up to 74 mph.
Associated Press reporters Tom Coyne in Indiana and Meghan Barr in Ohio contributed to this report.