Ontario, CA
Ontario wildfire risk explained
USFS scores Ontario at the 72nd national percentile for wildfire risk to structures (well above the national norm for wildfire risk), a figure built from 48,849 real buildings rather than raw vegetation cover. (Source: USFS's Wildfire Risk to Communities methodology.)
USFS's separate burn-probability score — fire likelihood alone, before counting what's built there — puts Ontario at the 77th percentile, close to its 72nd-percentile risk score.
What "at risk" means for the buildings here
Only 5.1% of Ontario's 48,849 buildings carry Direct exposure and 0% carry Indirect; the remaining 94.9% are Minimal, which shifts the risk driving this page's score toward the surrounding landscape rather than any one structure. At 48,849 buildings, this is a substantial built environment, so the shares below describe a real population of structures, not a handful of edge cases.
How Ontario compares
Ontario's 72nd national percentile looks worse in isolation than its 30th ranking inside California does — this place is on the milder end for its own state, by 42 points. Among the 31,521 US communities USFS scores, Ontario ranks 8,689 for wildfire risk (1 is highest) and 183 by building count (1 is largest). Within California alone, it ranks 1,094 of 1,570 places by risk. See the full county-by-county picture for California on its state page.
Shopping for coverage in Ontario
Ontario's 72nd-percentile score lands in California, the only two states requiring a wildfire disclosure at sale. California's surplus-lines homeowners market passed 300,000 policies for the first time in 2025, driven by carriers pulling back from wildfire-exposed areas statewide. The disclosure-law guide covers what it requires.
Lowering exposure, not just insuring around it
With 94.9% of buildings rated Minimal exposure, Ontario gets less benefit from structure hardening than a Direct- or Indirect-dominant place would — the home-hardening guide explains why the zone matters.
Where Ontario's figures come from
Ontario's 72nd-percentile score and its burn-probability figure both come from the same USFS workbook, documented in the methodology guide. The exposure-zones guide covers what Ontario's dominant minimal exposure actually means, with real examples from across the dataset.