Elmsford Mayor Robert Williams says the second home belongs to a town police detective.
Nobody has was injured in either home, but both familes were described as shaken.
The fires took place on Woodside Avenue.
Part of the home where the fire originally started has collapsed.
The Red Cross is putting the two families from 22 and 24 Woodside in hotels for the night. The Mayor said the community has already started gathering clothes for them.
The cause of the fire is under investigation.
Get Eyewitness News Delivered