This document summarizes two studies on health services at mass gatherings: 1. A case study of patient presentations from an outdoor music festival to onsite health providers, ambulance services, and hospitals. It found the most common issues were headaches, lacerations, and substance intoxication. Onsite care resulted in longer stays and potential avoidance of 15 hospital/ambulance transports. 2. A systematic literature review of the impact on health services from mass gatherings. It found minimal research focuses on impacts to ambulance and hospital services. More research is needed to better understand usage across events and collaboration between onsite and external health services.