Are there still any prairies left in the USA or have the all been farmed up?

The East European steppes have after all been completely farmed up, but since American praires have not been well known for non-nomadic peoples for so long there is still the possibility that some remain. And to make it clear, here I mean prairies that are genuine, and not restored and even less "urban prairies" (a tragic landscape-type created by urban decay).