No bidders submitted bids for two lots at 412 and 420 S. 5th St. in Boise at a foreclosure auction on Friday.
Washington Federal Savings Bank will retain ownership of the lots and the historic houses on them.
A grassroots group, Buffalo Heart Homes, had worked with Preservation Idaho to raise enough donations to buy the properties which the Ada County Assessor valued at just over $421,000.
By Friday, the groups had raised $7,500, far below the minimum bid of $460,000.
The Central Addition neighborhood, where the 1890-era houses sit, just north of Julia Davis Park, has been the focus of preservationists and city planners for several years. The area is home to fewer than 20 historic structures. It is not among the city's historic districts. Developers have expressed interest in razing some of the old houses and creating surface parking lots. The neighborhood also lost two buildings in a fire at the end of 2013. Preservationists say the neighborhood represents an important chapter in Boise's early history.
"We are uncertain what our next steps will be," said Dan Everhart, Preservation Idaho spokesman, "but hope that our donors will consent to let us keep their donations for further efforts in the neighborhood."