(And to preempt those who might question why anyone would both owning land: because like any investment there is a cost that can be exceeded by profit.)
It's not in the US, but the First Oil Well in Bahrain, which has been providing oil since June 2, 1932. For much of its life at 70,000 bbl/day, more recently at about half that rate, 35,000 bbl/day.
That's roughly $3.5 million per day in productivity.
There was a time, and Henry George came well after it, when the agricultural productivity of land was in fact the basis of virtually all wealth (some contributions from the sea, as well as water and wind power). Since the large-scale exploitation of coal, oil, and gas, starting in the mid 18th century, that hasn't been the case.
It eventually likely will be again, but I've not read enough of the Georgist view to see how the huge variances in land productivity would be addressed. Even if mere ag output is considered.