There are numerous possibilities, with the tax assessor's tax value in 2007 being the *absolute* *last* *resort*.
During the time it was owned by the person you inherited it from, did they rent it out or utilize the property for *any* business purpose, even if not 100% rental or business use? If so, then there's documents in their last tax return filed prior to their passing that may have that information in it. If not there, then it would be in the last tax return filed for the last tax year it was any degree of business use.
If there was a property appraisal done by a qualified appraiser (not the tax assessor) within the 2 years either side of their passing, then that appraised value will be sufficient.
