In the US it gets a little crazy: Land is separated out into square plots in quite a few places, especially the later-colonized west, think 'chessboard'. Companies buy all the white squares, leaving the black squares as public land. Which is now entirely inaccessible from anywhere except their private land.

Lots of shady duderanch companies do this.

There's an interesting legal dispute: Is crossing diagonally from one 'black square' to the next 'black square' tresspass? Technically unless you are infinitely tiny, your bulk does theoretically pass over white square.