The western Kentucky town of Mayfield was "ground zero" of the storm a scene of "massive devastation," one official said.
Multiple tornadoes ripped through five US states overnight.
Rescuers were desperately searching for survivors early Sunday after dozens of devastating tornadoes tore through six US states, leaving at least 83 people dead, dozens missing and towns in ruin.
US President Joe Biden called the wave of tornadoes, including one that travelled more than 200 miles, "one of the largest" storm outbreaks in American history.
"It's a tragedy," a shaken Biden, who pledged support for the affected states, said in televised comments. "And we still don't know how many lives are lost and the full extent of the damage."
Scores of search and rescue officials were helping stunned citizens across the US heartland sift through the rubble of their homes and businesses overnight.
More than 70 people are believed to have been killed in Kentucky alone, many of them workers at a candle factory, while at least six died in an Amazon warehouse in Illinois where they were on the night shift processing orders ahead of Christmas.