The fire started Wednesday on West Marshall Boulevard. Witnesses living nearby said they saw a man intentionally set the fire and taking off.
Firefighters were quickly able to control the flames. No damage to structures was reported.
San Bernardino police said on Wednesday one person was detained for potential arson. The individual's identity was not immediately released.
Both #hillsidefire and #marshallfire have been declared contained and are in the process of clean up. Streets are still blocked and we ask that you avoid the area. There was no structure damage in either incident and we have one subject detained for potential arson.— San Bernardino PD (@SanBernardinoPD) July 31, 2019
The fire scorched the area known as Little Mountain.
"The biggest threat was, there is a home over there that has some trees around it, and it was actually the home the McDonald's brothers built," said Daniel Blood.
The home once belonged to Richard McDonald, one of the famed brothers who founded McDonald's. He and his wife bought the home in 1951.
While the surrounding grass caught fire, the home was not damaged.
Residents credit firefighters and air resources for saving their homes.
Air resources are proving critical as a tool for firefighters and more are coming online.
Gov. Gavin Newsom and former Gov. Arnold Schwarzenegger visited a Cal Fire training base to view brand new C-130 air tankers.
The state is investing $127 million to expand Cal Fire's air fleet in response to the growing threat of severe wildfires.