Lot of very heavy primitive old iron rings, late 1800s vintage at our best guess. These were originally parts to some type of antique farm equipment, and came right out of a farm here in Wisconsin.
We aren't sure if these are cast iron or forged iron, as the finish is pitted from age and rust. They don't appear to have any markings.
There are two of the rings 4 1/2" across, one ring 6" across, and a 5" long oval with two smaller rings attached.