Cortland Firefighters were called to a fire in a basement of a home on Bartlett Street at about 10:40 Friday morning.
Deputy Fire Chief Wayne Friedman told X101 that everyone got out safely and the fire was put out quickly.
There was enough damage that the family will have to find another place to stay.
Friedman said Cortland and NYS Fire Investigators spent the rest of the day gathering evidence to try to determine the cause of the fire and have concluded at this time that the fire was started intentionally.
The circumstances are now the focus of a police investigation. City and state investigation results will be turned over to Cortland Police.