Land Value for Depreciation

[Patrick Shep]

if you’re figuring out the land value for depreciation purposes, can I use the Fair market value for the land? The county assessment taxes it at 59k which is WAY too high. A plot of land has sold for $8500, $10k and 29k within that area.  Can these be averaged together or even use the 29k? I don’t want any flags but don’t want to leave anything on the table For depreciation.