The fire broke out around 4:30 a.m. in a townhouse on Andrews Circle in Caln Township.
Arriving crews saw flames showing from the second-floor window. The fire quickly spread to a neighboring home.
It took crews one hour to bring the fire under control.
Chopper 6 over the scene showed the severe damage to at least three townhomes.
3-alarm fire severely damages Chester County townhomes
No injuries have been reported.