The church was empty at the time. There were no injuries.
The church has about 100 active members. Services were held Sunday at the Fulton Theater Welcome Center in McConnellsburg, said the Rev. David M. Carroll, pastor.
Steve Haskins, spokesman for the federal Bureau of Alcohol, Tobacco and Firearms office in Philadelphia, said ATF agents are assisting state fire marshals in their investigation of the cause of the fire.
Haskins said so far their is no connection to arsons that damaged or destroyed the western Pennsylvania churches in Allegheny, Butler, Westmoreland and Somerset counties. The most recent was last month at the Calvary Baptist church in Saxonburg, about 20 miles north of Pittsburgh.
Like Calvary Baptist, the other seven churches have a mostly white congregation, in contrast to a series of arsons that destroyed several black congregation churches in the South several years ago.
Since then, Haskins said, President Clinton has ordered ATF agents to be present in any investigation involving church fires.
"We've been telling police agencies all over the country that we have to be notified. We don't take over investigations, but we have to be there to assist," he said.
Carroll said Sunday's services in the theater building were "a time of weeping and a time of rejoicing because we know God will rebuild our church." The congregation was founded 35 years ago. The church, a brick building with a basement that housed a classroom, kitchen, pastor's study and library, was built 28 years ago, Carroll said.
He said the church has insurance, but wasn't sure if it would cover the total loss.
Anyone wishing to help the church can call 1-717-485-5447.
The Associated Press contributed to this story.