The children's parents escaped. Their father jumped off the porch roof of the two-story house and was trying to coax one of his children to do the same when the roof collapsed, fire Capt. Mike Washington said.
"When one of the battalion chiefs arrived in his car, he saw the girl on the roof of the porch," he said. "She was lost in the fire."
A neighbor told CBS affiliate WKRC-TV the children were Julia Hulett, 9, Jasmine Hulett, 5, and Robert Hulett Jr., 2. Their father, Robert Hulett, was taken to a hospital for treatment and is listed in serious condition, authorities said.
The children's mother, April Hulett, was not hurt.
Officials at Julia Hulett's school say they've set up a memorial to the girl in the school's office, which includes photos and candles. Her classmates are decorating her desk today in tribute and counselors are on hand to help them work through the loss, reports WKRC.
Two fire crews arrived at the house in Cincinnati's Lower Price Hill neighborhood around 2:30 a.m. about two minutes after a series of 911 phone calls, Washington said. More than 50 firefighters battled the blaze.
"We fought hard," Washington said. "It was an intense fire and it was a valiant effort on the firefighters' part."
The cause of the fire has not been determined.