Union City, CA
How exposed is Union City to wildfire?
Union City sits at the 95th percentile nationally for wildfire risk to structures — in USFS's highest wildfire-risk band nationally — per USFS's Wildfire Risk to Communities model, built from its 17,307 counted buildings, not vegetation cover alone. (Source: USFS's Wildfire Risk to Communities methodology.)
USFS's separate burn-probability score — fire likelihood alone, before counting what's built there — puts Union City at the 95th percentile, close to its 95th-percentile risk score.
Where Union City's buildings actually sit
USFS puts 62.8% of Union City's 17,307 buildings in the Indirect exposure zone, versus 0.9% Direct and 36.2% Minimal — a place where the fire doesn't need to reach the structure directly for embers to. At 17,307 buildings, this is a substantial built environment, so the shares below describe a real population of structures, not a handful of edge cases.
Where Union City ranks
Union City's 95th national percentile looks worse in isolation than its 73rd ranking inside California does — this place is on the milder end for its own state, by 22 points. Among the 31,521 US communities USFS scores, Union City ranks 1,697 for wildfire risk (1 is highest) and 826 by building count (1 is largest). Within California alone, it ranks 431 of 1,570 places by risk. See the full county-by-county picture for California on its state page.
Union City and the insurance market
Union City sits in California, one of two states that legally require a wildfire-risk disclosure at sale. California's FAIR Plan, the state's insurer of last resort, ended 2025 with 668,609 residential policies after adding 21,859 in Q4 alone — the kind of market shift a 95th-percentile score like Union City's can end up mattering for. More on the disclosure law.
What would actually reduce this score
Union City's 62.8% Indirect-exposure share points at embers, not flame contact, as the main pathway — ember-resistant vents and non-combustible roofing rank ahead of defensible space here. Detail in the home-hardening guide.
Where Union City's figures come from
The methodology guide shows exactly how USFS turned 17,307 counted buildings into the percentiles shown above for Union City. The exposure-zones guide covers what Union City's dominant indirect exposure actually means, with real examples from across the dataset.