On the night of September 1, 2017, a mass shooting occurred near the Las Vegas Strip during the Route 91 Harvest country music festival on the Las Vegas Strip’s eastern edge. The attack unfolded from a high-rise hotel room and resulted in a large number of fatalities and injuries, prompting an immediate law-enforcement and emergency medical response. In the hours after the shooting, law enforcement established a perimeter and closed sections of the Las Vegas Strip and adjacent roadways to allow first responders to treat the wounded, conduct searches, and gather evidence. The closures affected traffic, public transit routes, and business operations in the area as officials worked to secure the scene and provide public safety guidance. Local, state and federal agencies were involved in the response and subsequent investigation. Hospitals in the Las Vegas valley received a surge of patients, and emergency services set up triage and transport operations. Investigators focused on determining the assailant’s location, potential motives, and whether there were any accomplices. In the days that followed, authorities searched the suspect’s hotel room and other properties linked to him for evidence. Officials used media briefings and social media to update the public on closures, evacuation orders, and transportation disruptions. The closures were lifted gradually as areas were cleared and victims were treated or transported. The incident prompted reviews of venue security, emergency preparedness, and communication procedures for large public events. The shooting had a significant human toll and led to widespread grief and calls for changes in public-safety measures at concerts and outdoor gatherings. Accurate casualty figures and details about the investigation were provided by law-enforcement agencies and hospital officials in the period following the attack. The event remains one of the deadliest mass shootings in modern U.S. history and had lasting impacts on victims, families, first responders, and the Las Vegas community.