The private family-owned winery, established in 1979, is located along the popular Silverado Trail, an area that came under mandatory evacuation orders on Sunday as the Glass Fire grew from a relatively small 20-acre vegetation fire to burn 11,000 acres.
Photos show flames completely taking over the stone chateau as firefighters worked to contain them Sunday night.
Chateau Boswell, located in in St. Helena, is known as one of just a handful of privately owned family wineries remaining in Napa Valley, according to its website.
Video posted to Twitter by CNN affiliate KGO reporter Amy Hollyfield shows the charred remains of the chateau while nearby trees still burn.
The Black Rock Inn, another popular destination in St. Helena, was also destroyed in the fire, according to its former owner, Jeff Orlik.
Orlik told CNN that he sold the inn two years ago and the new owners had been working on the property during that time. It wasn’t currently open to lodgers.
There are dozens of wineries in the area, three of which – Reverie Winery, Viader Winery and Davis Estates winery – are also threatened by flames, according to KPIX.
Flames have forced tens of thousands of evacuations throughout Napa and Sonoma counties, officials say.
CNN’s Alta Spells contributed to this report.