It looks like there are side-to-side grooves in the inner hole. If so, I'd say it's from a piece of agricultural equipment. Doesn't look "extremely" old - guess that depends a lot on what your soil conditions normally do to steel.
...Doesn't look like anything that would have normally come in contact with the ground, so probably some piece to hold up the part of the machine that did contact the soil.
my 2¢