Wildfires can happen in many places in the United States, especially during droughts, but are most common in the Western United States and Florida.[3] They may be triggered naturally, most commonly by lightning, or by human activity like unextinguished smoking materials, faulty electrical equipment, overheating automobiles, or arson.
Fire management policy favored aggressive wildfire suppression starting in the early 20th century.
In the 21st century, higher temperature and droughts driven by global warming have become more of a concern, and there has been increased advocacy for controlled burns and other measures to prevent fuel from accumulating in wild areas that can create more intense, larger, and difficult-to-control fires.
Firefighters are generally employed by governments, including municipal and county fire departments, regional mutual aid organizations, and state agencies like the California Department of Forestry and Fire Protection and the New Jersey Forest Fire Service. Wildfire response is coordinated at the federal level by the National Interagency Fire Center, with the participation of the U.S. National Weather Service, and various agencies of the Departments of the Interior, Agriculture, Homeland Security, and Commerce. Fire squadrons of the United States Army are also sometimes called to large fires.