By Gina Keating

LOS ANGELES (Reuters) - California firefighters held the line overnight on two wildfires burning along the California coast that threatened more than 4,000 homes and other structures, fire officials said on Friday morning.

The Basin Complex and Gap fires, burning about 170 miles (273 km) apart, were both unusually active overnight but firefighters managed to stop the flames, in some cases at the doorsteps of homes.

The Gap fire, burning north of Goleta, is considered the top priority among more than 1,000 blazes burning across the state because of its proximity to homes.

Although the blaze more than doubled in size to 5,400 acres (2,185 hectares), firefighters turned it away from Goleta, a town of 30,000 people about 100 miles (160 km) northwest of Los Angeles, and from power lines that supply the central California coast, said Santa Barbara County spokesman William Boyer.

"Our firefighters made some pretty heroic stands last night," he said.

Mandatory evacuations and evacuation warnings, in which residents must be prepared to leave, remain in effect for 1,900 homes, Boyer said.

A fleet of 20 firefighting aircraft began dropping water and retardant on the flames on Friday, and weather conditions were "a little overcast and a little muggy," Boyer said.

"If we get more of that, that's a good thing," he said.