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Background Out-of-hospital cardiac arrest (OHCA) shows marked geographic variability. Socio-economic deprivation may contribute to this variability, but evidence from mixed urban–rural regions remains limited. We aimed to identify spatial clusters of OHCA incidence in northern France and to assess whether these clusters were associated with deprivation, care processes and outcomes.Methods We conducted a retrospective, population-based cohort study using data from the French National Out-of-Hospital Cardiac Arrest Registry for all OHCAs managed by mobile intensive care units between 1 July 2015 and 30 June 2016 in Nord-Pas-de-Calais. Age-adjusted and sex-adjusted standardised incidence ratios were smoothed with a Besag-York-Mollié Bayesian model. Spatial scan statistics identified incidence clusters. Cluster-level socioeconomic indicators, care processes and outcomes were comparedResults Incidence was mapped across 1541 municipalities. Among 2867 OHCAs, mean annual OHCA incidence was 68.8 per 100 000 inhabitants (range <0.5 to >1.5 across municipalities). Two high-incidence clusters (relative risk between 1.61 and 1.68) and three low-incidence clusters (relative risk between 0.48 and 0.66) were detected. High-incidence clusters displayed greater deprivation and lower median income. Bystander basic life support was less frequent (26.7%) and 12-month survival lowest (1.4%) in the most deprived cluster.Conclusions Pronounced spatial inequality in OHCA burden exists within northern France. Municipalities with higher deprivation experience disproportionately higher incidence and poorer long-term survival. Targeted cardiopulmonary resuscitation training and strategic automated external defibrillator deployment should prioritise these vulnerable communities.