Companies have ‘personhood,’ ie. a legal identity equivalent to people in the sense that they can enter into contracts and agreements (see Wikipedia article). This is a subject of considerable argument, and there are several campaigns to remove this status.
On the other hand in New Zealand there is a move (reported in the New Zealand Herald here) to give a river the status of a person, for the river to have a legal identity. If we accept that all things have agency, not just human beings, this legal recognition of the personhood of a river, developed from the indigenous knowledge tradition and by the Whanganui River Iwi, is incredibly important.
To give a river (or presumably a mountain, valley or island) this status of personhood is important because it repositions us, human beings, within the environment, rather than over it.
Where the problem with corporate personhood is that it requires the law to respect corporate interests as equivalent to the interests of people, the positive benefits of giving at least some natural features some legal agency or status as persons is potentially transformative.
The recognition of indigenous knowledge traditions is of course also enormously positive and challenging to Western epistemologies. If the river is a person, what does the river know, and how do we value that form of knowledge.