The tropical storm brought flooding and destruction to southwest Florida, mostly affecting Fort Myers, Fort Myers Beach and Cape Coral.
Tallied by NBC News, the number is feared to continue to rise.
In North Carolina, there were four storm-related deaths due to Ian.
Rescue efforts remain underway after the devastating Category 4 storm made landfall Wednesday.
President Joe Biden said Thursday that Hurricane Ian "could be the deadliest" in the state's history.
"This could be the deadliest hurricane in Florida's history. The numbers are still unclear, but we're hearing early reports of what may be substantial loss of life," Biden said from Federal Emergency Management Agency (FEMA) headquarters.
This week, Biden and first lady Jill Biden are expected to travel to Florida.
