The fire broke out around 1 a.m. at the Veterans of Foreign Wars Post 5886 building on Rose Street in Smithfield.
Flames were seen pouring out of the 3500 square foot building when firefighters arrived.
The left side of the building had suffered extensive damage by the time crews extinguished the blaze. No one was hurt.
Following an investigation, authorities ruled the fire was accidental.
"After the fire was out they did manage to get the American flag out, the one that I imagine they salute to, and another flag. It was kind of neat," neighbor Rachel Roberts said.
Veterans said documents, pictures, flags and other artifacts salvaged from the charred interior by firefighters are links to the warriors who gathered at the building for more than six decades.
It is unclear where the VFW will meet next, but a new building could be built in the same spot where the gutted building currently stands.