An unoccupied house is on fire at Smith's Mount St. Helena Trout Farm and Hatchery, Sonoma County fire dispatchers said.

Firefighters from six agencies were called to the blaze on Ida Clayton Road at 2:34 p.m. Dispatchers said the fire was contained to an unoccupied structure and had not spread to surrounding vegetation.

No lives were threatened, dispatchers said.

The trout farm is located in a wooded area on the north slope of Mount St. Helena.

Cal Fire, Geyserville Fire, Knights Valley Fire, Healdsburg Fire, Dry Creek Fire and Mountain Fire all responded.