Wildfires occur across every region of the United States, but they concentrate heavily in the West. Between 1999 and 2017, nearly half of all large wildfires (those burning 500 acres or more) happened in western states, with California, Oregon, Washington, Montana, Idaho, and Colorado seeing the most activity. The Southeast and Great Plains also burn frequently, though fires there tend to behave differently and attract less national attention.
The Western States
The West dominates wildfire statistics for straightforward reasons: large stretches of dry vegetation, rugged terrain, and a climate that delivers hot, rainless summers. Of roughly 12,000 large wildfires mapped across the lower 48 states from 1999 to 2017, about 5,900 burned in the western region. That’s nearly double the count of any other part of the country.
California stands out even within the West. The state’s chaparral shrublands alone cover about 8.4 million acres, much of it on steep slopes bordering dense urban areas. Chaparral is extremely flammable during the long dry season, and when it ignites, it burns as intense crown fire that moves fast through continuous canopy. Add Santa Ana winds in the fall and you get the conditions behind many of the state’s most destructive fires. Oregon, Washington, and the Northern Rockies (Montana, Idaho, Wyoming) see enormous fires too, often in conifer forests and grasslands where lightning storms in summer can spark blazes across remote landscapes.
The Southwest, including Arizona and New Mexico, averages 55 fire weather days per year, the highest of any region in the country. Fire weather days are those where temperature, humidity, and wind combine to make fire spread easy. That number has climbed by 37 days since the early 1970s, meaning the Southwest’s fire-prone window has more than doubled in half a century.
The Southeast and Eastern States
The Southeast burns more often than most people realize. About 2,800 large wildfires struck the eastern region over that same 1999 to 2017 period, and much of that activity centered in the coastal Southeast. Historically, the longleaf pine grasslands stretching across the Coastal Plain from Texas to the Carolinas had a natural fire cycle of every two to five years, making it one of the most frequently burned landscapes on the continent despite its humid, wet climate.
Fires in the East behave differently from those in the West. The types of vegetation that produce a large fire in the East wouldn’t necessarily sustain one in the West, and vice versa. Eastern fires often burn through herbaceous wetlands, crop margins, and open developed land rather than the dense shrub and forest fuels that drive western megafires. Florida, Georgia, and the Carolinas see regular wildfire activity, particularly in spring when dormant vegetation dries out before the summer rains arrive.
The Great Plains and Central Region
The central United States recorded about 3,250 large wildfires from 1999 to 2017, placing it between the West and East. Grassland fires across Kansas, Oklahoma, Nebraska, and the Dakotas can be enormous in acreage because flat terrain and steady wind push flames across open land with little to stop them. The 2017 fires in the Texas and Oklahoma panhandles burned hundreds of thousands of acres in days.
Grasslands and herbaceous vegetation are the single strongest predictor of where large fires occur nationwide. Crops and pasture actually act as firebreaks, fragmenting the fuel enough to slow or stop fire spread. That means the patchwork of farmland across the Plains limits some fires while the remaining native grassland corridors remain highly fire-prone.
Alaska
Alaska is in a category of its own. Its boreal forests and tundra burn in massive, remote fires that rarely threaten large populations but can consume millions of acres in a single season. Lightning is the primary ignition source, and long summer daylight hours dry out the landscape. Alaska’s fire seasons have grown more intense in recent decades as warming temperatures thaw permafrost and dry out organic soils that historically stayed too wet to burn.
What Starts the Fires
Humans start 84% of all wildfires in the United States, and 97% of fires that directly threaten homes. That includes equipment sparks, power lines, campfires, arson, and debris burning. Lightning accounts for most of the rest, and while lightning fires are less common, they tend to ignite in remote areas where they can burn unchecked for longer before detection.
The human-caused majority explains why wildfire risk doesn’t just follow dry climates. Anywhere people live near burnable vegetation, fires start. That’s true in New Jersey’s Pine Barrens, the Appalachian ridges, and suburban edges of every major western city.
Fire Seasons Are Getting Longer
Every region of the country has seen its fire weather season expand since the early 1970s, but the increases are starkly uneven. The Southwest gained 37 additional fire weather days, and the broader West gained 21. The Northwest picked up 9 extra days, almost entirely concentrated in summer. Spring has been the fastest-growing fire season across most of the West, with the Southwest adding 16 spring fire weather days alone.
Eastern regions have seen smaller but consistent increases of 1 to 2 additional fire weather days. The Northeast averages 11 fire weather days per year, while the Upper Midwest and Ohio Valley average just 4. These numbers are low compared to western states, but even small increases in fire weather push regions that aren’t accustomed to wildfire into unfamiliar risk.
The practical takeaway: wildfires are a western problem by volume and intensity, a southeastern problem by frequency, a Plains problem by sheer acreage, and an Alaskan problem by scale. No region is immune, and the geographic footprint of high fire risk is expanding in every direction.