"On October 1, 2017, over 22,000 people attended the Route 91 Harvest Festival in Las Vegas, Nevada. On the third and final night of the festival, a lone gunman opened fire into the crowd from the 32nd floor of the Mandalay Bay Resort and Casino. The gunfire continued for over ten minutes, resulting in the deaths of 58 people and injuring more than 850, including first responders. Two local police officers responding to the incident were among those wounded by gunfire. As the shooter engaged in this horrific act of mass violence, first responders made quick decisions, acting with bravery and professionalism to secure the scene and save lives. The cooperation between local fire departments, law enforcement agencies, and local private ambulance companies at the scene was exceptional. Off-duty public safety personnel also assisted in the response, providing valuable surge support for local responders. The Las Vegas community as a whole came together in response to this unprecedented situation to assist the survivors and responders of the shooting. In the wake of this incident, it is important to evaluate the strengths and areas for improvement observed during the response--both to enhance the internal response capabilities of the Clark County Fire Department (CCFD) and the Las Vegas Metropolitan Police Department (LVMPD), as well as to share the knowledge gained from this incident with public safety agencies from across the country to assist in their preparedness efforts."