NW Ohio, where my parents live. I know a little more than usual because the state is coming through buying land for a new highway.
Some farm land that was converted into residential lots (not in town) went for $15,000/acre. The land isn't anything special, flat and no trees.
The state is paying far less than that for land. I've heard people say anywhere from $2,000 to $7,500 an acre (the $7,500/acre was for land that was essentially the same as the land that went for $15,000/acre to a person).
A farm went up for sale recently, I think the guy who bought it all paid around $3,000/acre, but that also included a farmhouse (not in great shape). He bought the whole farm as one lot at auction.
My great uncle lives on the edge of town and has a house, outside building, and 30 acres. He was talking about how the estate would eventually be split up and we estimated that if all his land was split into residential lots, the whole thing would probably be worth around a million dollars.