After three and a half years of attempting to save a 19th-century home from an uncertain future, Lynn Hyde is trying to remain hopeful in the face of a looming fundraising deadline.

The nonprofit group, Historic Whidbey, has been leading a campaign to raise $250,000 to acquire the 1866 Haller House in Coupeville but so far has only raised about $25,000, with a May 19 deadline approaching.

“We are scrambling like crazy to try to dig a little more treasure out of the ground,” said Hyde, the group’s president. “Really, everything above ground, we’ve already hit.”

The preservation group recently received a boost when an anonymous donor from Seattle challenged others by offering to donate $50,000 toward the house if others will match that amount.

Historic Whidbey wants to purchase the house from the McPherson family in Coupeville and turn it into a heritage and visitor center for public benefit, as well as a pioneer store.

The center would be a showcase of Washington’s territorial period before statehood came in 1889, Hyde contends. Coupeville has the highest concentration of surviving territorial-era structures in Washington, she said.

By matching the recent pledge, Hyde is hopeful it could create some late momentum.

“We would begin to be in shouting distance,” Hyde said.

If the money isn’t raised, the view home on Front Street likely would be placed on the market with its fate undetermined.

The Haller House was placed on the Most Endangered Historical Properties list in 2013 by the Washington Trust for Historic Preservation.

Historic Whidbey is hosting one final open house to show the home built by Col. Granville Haller from 10 a.m. to 4 p.m. May 14 during the Penn Cove Water Festival.

“I think the message to take away from this is we all love our historic community and we love the heritage here,” Hyde said. “But it takes vigilance. It’s never done. Once these houses are gone, they’re never coming back.”

For more information about the house or how to contribute, visit www.historicwhidbey.org