Photo: The Canadian Press

Satellite image shows smoke from wildfire near Yosemite National Park in California.

The town of Mariposa, with its century-old saloons and covered sidewalks, normally bustles with summer visitors on their way to Yosemite National Park, but the Gold Rush-era hamlet was mostly empty as ash rained down and heavy smoke from a nearby blaze darkened the sky.

The blaze in the Sierra Nevada foothills threatened hundreds of homes and historic buildings, including a wood courthouse founded in 1854 and touted as the oldest active courthouse west of the Rocky Mountains.

The fire did not grow as significantly Thursday as it had earlier in the week, but state fire officials revealed late in the day that 99 structures have now been destroyed, 50 of them homes. Eleven homes and five other structures have been damaged. The wildfire has scorched 110 square miles, threatening at least 1,500 homes.

More than 3,000 firefighters are battling the blaze that has forced almost 5,000 people from homes in and around a half-dozen small communities. It is 10 per cent contained.

Only fire trucks and other emergency vehicles travelled Thursday on Highway 140, the main road to Yosemite National Park and the town's main street.