Objective: Rates of suicide, suicidal ideation and self-harm are higher in regional and remote areas of Australia. This study aimed to examine the regional co-occurrence of adolescent suicidal ideation/self-harm and adverse childhood experiences, with consideration of area-based indices of socio-economic disadvantage and remoteness and the availability of mental healthcare professionals in New South Wales (NSW). Methods: Participants were 73,883 young people, born between 2002 and 2005, represented in the NSW Child Development Study (NSW-CDS) – a record-linkage study utilising Commonwealth and State government records. Aggregated longitudinal data according to statistical areas of residence were used to geographically map adolescent suicidal ideation/self-harm against prior adverse childhood experiences, socio-economic disadvantage, geographical remoteness and the number of mental healthcare professionals per region. Results: The average number of adverse childhood experiences and the proportion of children residing in areas of socio-economic disadvantage and geographical remoteness were strongly associated with the regional incidence of suicidal ideation/self-harm. Associations between the incidence of suicidal ideation/self-harm and the number of mental healthcare professionals in each region were not significant in adjusted models. Young people growing up in regions outside of Greater Sydney, particularly those in north-west NSW, had the greatest exposure to early adverse childhood experiences, the highest proportion residing in socio-economic disadvantaged and geographically remote areas and the highest incidence of adolescent suicidal ideation/self-harm. Discussion: These findings have policy implications for the geographic allocation of resources to prevent self-harm and suicide in young people. Early-life interventions should be aimed at reducing adverse childhood experiences.