The order was issued Tuesday afternoon, hours after authorities closed nearly 111 square miles of the Los Padres National Forest.
Forest Service spokesman Maeton Freel says most of the closed area is inaccessible backcountry. He says ranchers are moving their horses and other livestock.
The 4-day-old wildfire in the San Rafael Wilderness area of the forest has scorched more than 32 square miles of brushy canyon lands and crested a ridge a few miles from the ranches.
More than 1,000 firefighters are battling the blaze. It's 10 percent contained.