A landmark political decision recognising the legal personhood of a river provides insights into how legal pluralism may evolve and how relationships with non‐human nature may be recognised into the future. The decision in respect of the Whanganui River in Aotearoa/New Zealand, although not a legal precedent, has resulted in a new and vital Māori/Pākehā legal arrangement, which, in addressing the injustices of the country's colonial history, may also address environmental challenges such as resource exploitation. Since colonisation in 1840, the Māori of the Whanganui River have been fighting to assert their rights in relation to the river. The 1840 Treaty of Waitangi, made between Māori chiefs and British colonisers as the basis of future governance in Aotearoa/New Zealand, was flawed due to differences between the Māori and English versions of the Treaty. Conflicting expectations regarding the constitution and administration of “law” emerged, as did incompatibilities between Māori and English ontologies, particularly involving interactions between humans and (non‐human) nature. In 1975, a tribunal was established to resolve Māori grievances regarding application of the principles of the Waitangi Treaty. In 1999, the Tribunal settled Claim 167 (known as Wai 167, after the Tribunal), recognising Māori ownership of the Whanganui River. Subsequent negotiations resulted in declaration of the river's legal personhood; the enacting legislation was passed on 20 March 2017. An association of place‐based law and the dominant legal system has been instigated. This paper explores how this less anthropocentric approach, in an era commonly called the “Anthropocene” due to the influence of humans on planet Earth, has a critical role to play in environmental management, particularly in relation to water.