Objective: Resuscitation from out-of-hospital cardiac arrest (OHCA) is largely determined by the availability of cardiopulmonary resuscitation (CPR) and defibrillation within 5–10 min of collapse. The potential contribution of organised groups of volunteers to delivery of CPR and defibrillation in their communities has been little studied. Ireland has extensive networks of such volunteers; this study develops and tests a model to examine the potential impact at national level of these networks on early delivery of care. Methods: A geographical information systems study considering all statutory ambulance resource locations and all centre point locations for community first responder (CFR) schemes that operate in Ireland were undertaken. ESRI ArcGIS Desktop 10.4 was used to map CFR and ambulance base locations. ArcGIS Online proximity analysis function was used to model 5–10 min drive time response areas under sample peak and off-peak conditions. Response areas were linked to Irish population census data so as to establish the proportion of the population that have the potential to receive a timely cardiac arrest emergency response. Results: This study found that CFRs are present in many communities throughout Ireland and have the potential to reach a million additional citizens before the ambulance service and within a timeframe where CPR and defibrillation are likely to be effective treatments. Conclusion: CFRs have significant potential to contribute to survival following OHCA in Ireland. Further research that examines the processes, experiences and outcomes of CFR involvement in OHCA resuscitation should be a scientific priority.