@sandorbatyi was your mother a United States person for tax purposes in the year that she made the gift? If she was a United States person (a citizen or resident alien) then she would need to file a gift tax return to report the gift of the house. And you could do that now as the administrator of her estate. But if she was not a US person, then she would have no obligation to report a gift to the IRS.
Is there property tax in Hungary and is it calculated on the value of the property? If so, the tax records in 2007 or 2008 might be a good estimate of the value when new.
