M aori land data produced through colonial systems of dispossession lack interoperability, preventing kin-based communities from tracking their land. Our novel approach to repatriate and harmonise historic land data traces the history of the 45,500 acre Opuatia Block allocated to hap u Ng ati Tiipa in 1866, following the confiscation of 1.2 million acres of Waikato land. Ng ati Tiipa resisted Crown and settler pressures for 30 years, but 80% of Opuatia was alienated within a decade. We discuss the devastation of 'judicial raupatu' and the implications of this work for hap u data sovereignty and wider international efforts to achieve Indigenous data sovereignty.