PORT TOWNSEND — The Jefferson County Historical Society expects to gather its half-million documents, 20,000 photographs and 20,000 artifacts under one roof after it opens a $2 million, 8,000-square-foot expansion of the research center in October 2010.

Friday’s announcement of the project will be followed in about a week with reports of major private donations, and perhaps grants, that will fuel the expansion, said Bill Tennent, historical society director.

“We will probably have half the money that we need,” he said.

The plans are to turn the existing 2,000-square-foot research center on Airport Cutoff Road — or state Highway 19 — that opened in 2003 into one wing of a 10,000-square-foot facility, Tennent said.

The expanded center will include a new lobby and reception area, meeting space for school groups and classes, a studio apartment for college interns, a conservation laboratory and processing area for incoming artifacts, additional work stations and computer terminals, and more storage space.

The present building will house large artifacts, such as agricultural machinery and furniture, while the additional 8,000-square-feet will provide climate-controlled space for maps, diaries, letters, government records, business ledgers, campaign materials, house wares, clothing, thousands of buttons and other archives and artifacts, as well as the reference materials of the Jefferson County Genealogical Society, a partner in the facility.

Collected together will be material that now is scattered over several locations.

Fort Worden State Park has provided storage space on the floor above the Coast Artillery Museum, the basement of the Peninsula College building and one of the bunkers, Tennent said.

“We have to give thanks to Fort Worden because they have allowed us to use space there for many years,” he said.

Those collections must be relocated, because of plans to create a life-long learning center at Fort Worden, he added.