On Friday morning, the historic “South San Francisco The Industrial City” sign based on San Bruno Mountain was engulfed in smoke as a vegetation fire spread.
The South San Francisco Hillside Sign was created in the 1920s and is listed on the National Register of Historic Places.
Although the area around the sign was badly burnt, its concrete letters appeared to be intact, according to NBC Bay Area.
Fire crews responded to the incident soon after the blaze broke out on Sign Hill, while evacuation orders were sent out for the nearby homes as the flames spread towards residential areas.
A temporary evacuation centre was set up at a local social hall near the hill, the South San Francisco Fire Department told CBS 5.
Aerial crews from the department dropped a flame retardant spray around the homes by Sign Hill, in an attempt to protect residences from the blaze.
After several residents attempted to film the flames from the sky, the fire department tweeted a message from its fire chief Jesus Magallanes.
“Safety is our number one priority. Please help us keep everyone safe by keeping your drones away from this incident,” the tweet read.
At least one house in the area had caught fire by Friday afternoon, according to San Francisco First.
San Francisco, alongside other areas of the US West Coast, has been ravaged by wildfires over the last few months.
At least 71 large fires have burned across West Coast states, as more than four million acres in California and one million in Oregon have been destroyed this year.