Recognition of legal personhood in contemporary international and domestic law is a matter of signs. Those signs identify the existence of the legal person: human animals, corporations and states. They also identify facets of that personhood that situate the signified entities within webs of rights and responsibilities. Entities that are not legal persons lack agency and are thus invisible. They may be acted on but, absent the personhood that is communicated through a range of indicia and shapes both legal and popular understanding of powers and obligations, they lack standing in judicial fora. They are signified as entities that are the subjects of action by legal persons, for example exploitation through rights regarding natural resources or commodification of ‘wild’, companion and other non-human animals. They are also signified as members of a diverse class of non-persons such as ‘nature’ and ‘the environment’. This article explores the consequences of law’s signification of personhood and the natural world before asking whether we both should and could recognise domains such as specific rivers, forests or even Antarctica as a type of legal person. Recognition might acknowledge the salience of nature in the ontologies of colonised First Peoples. It might also underpin a global response to climate change as the existential crisis of the Anthropocene. In understanding law as a matter of signifiers and syntaxes the article cautions that ostensible recognition of some domains as persons has been aspirational rather than substantive, with observers misreading the sign as necessarily transforming power relationships. The article also cautions that personhood for nature or particular domains may be contrary to the self-determination of colonised First Peoples.