Abstract Introduction In 1999, the first Local Health Unit (LHU) was created in the Northern region of Portugal to improve management, share resources and integrate care. The LHU integrated a National Health Service (NHS) hospital and primary healthcare (PHC) services located within the same geographic area and became responsible for public health activities and the provision of care. Over the next few years, 7 LHUs were created, the last one in 2012. In 2024, the government expanded this model to the entire territory, creating 39 LHUs. This research analyses the objectives, characteristics and expected outcomes of the scale-up of LHUs. Methods This study utilised a mixed methods approach based on the 6 Ps - Problem, People (policy stakeholders), Process (policy development), Price tag (Resource allocation), Paper (policies, laws, regulations), Programmes (policy implementation); and the political, social and economic setting of the Policy Circle Framework. Findings A 2015 assessment revealed that LHUs did not differ from non-LHUs in terms of access, waiting times, clinical excellency, patient safety or patient centeredness. The degree of integration of care in LHUs seemed lower compared with non-LHUs. However, there was no systematic evaluation of the creation of the first LHU. Despite this, the government announced the intention to expand LHUs to the entire national territory, which culminated with the creation of 39 LHUs in 2024 to deliver integrated care, with an emphasis on the proximity and continuity of health services and promotion. Conclusions Despite the existing knowledge gap on the impacts of LHUs in health outcomes and management efficiency, LHUs can provide opportunities to advance integrated and patient-centred care and develop strategies for managing scarce resources, including the health workforce. Nevertheless, the integration of hospitals and PHC can threaten the centrality of primary health care both in terms of delivery of care and resource allocation.