Firefighters say it started in a detached carport in Millcreek, but quickly spread to both homes because of their close proximity.
At one point, there were 63 different fire units on scene, and more than 75 firefighters.
It took about 40 minutes to get the fire under control, and the cause is still under investigation.
Both families in the home were able to get out without any injuries, but are having to find alternate living arrangements this morning.
Donations can be made to the Draper Family Relief Fund at Mountain America Banks.