Ontario, California

The same ground, surveyed 85 years apart. Drag the handle to wipe between them. Both sheets are United States Geological Survey originals; neither has been altered.

1897 1982

Buildings and businesses the archive holds for this place. Each opens its own page, with the source record it came from.

On the National Register 5 records

• Dr. Orville S. Ensign Houselisted 2012
• Frankish Buildinglisted 1980
• Hofer Ranchlisted 1993
• Ontario State Bank Blocklisted 1982
• Ontario Baseball Parklisted 2021

Ontario grew from 683 to 175,265 between 1890 and 2020. These are the recorded population figures Wikidata holds for this place, reached through the Geographic Names Information System number this page is keyed on rather than by name, so they belong to this place and not to another of the same name. Most are census counts, but not all are: an early figure may be a founding or settlement estimate, and an estimate published within five years of a census is left out. The change column is computed, and is left blank where more than 20 years separate a figure from the one before it, because a gap that long is not a change between two counts.

Matched by testing this settlement's coordinate against the published boundary of every sheet in the United States Geological Survey's historical collection. Each opens the scanned sheet at the Survey.

• 1897 USGS Cucamonga quadrangle1:62500
• 1900 USGS Cucamonga quadrangle1:62500
• 1901 USGS Southern California Sheet No. 1 quadrangle1:250000, 6 printings
• 1903 USGS Cucamonga quadrangle1:62500, 11 printings
• 1904 USGS Southern California Sheet No. 1 quadrangle1:250000, 2 printings
• 1933 USGS Ontario quadrangle1:31680
• 1942 USGS Ontario and Vicinity quadrangle1:31680, 2 printings
• 1944 USGS Cucamonga quadrangle1:62500
• 1953 USGS San Bernardino quadrangle1:250000, 2 printings
• 1954 USGS Ontario quadrangle1:24000, 2 printings
• 1954 USGS Ontario quadrangle1:62500, 5 printings
• 1956 USGS San Bernardino quadrangle1:250000
• 1957 USGS San Bernardino quadrangle1:250000
• 1958 USGS San Bernardino quadrangle1:250000
• 1959 USGS San Bernardino quadrangle1:250000
• 1966 USGS San Bernardino quadrangle1:250000
• 1967 USGS Ontario quadrangle1:24000, 3 printings
• 1982 USGS San Bernardino quadrangle1:100000

Regional context, not property-specific evidence. The federal wildfire occurrence database lists 267 fires within 5 miles of Ontario between 1992 and 2020, burning about 270 acres in total. 3 started naturally. 33 were recorded as arson. Distance is straight-line from the map coordinates, so a fire counted here may appear on a neighbouring settlement's page as well.

The most recent of them, most recent first, with the day each was reported and the service that recorded it.

Settlements close enough to share some of these fires:

• Narod
• Sunsweet
• Montclair
• Ballou
• Racimo
• Chino

Every fire recorded in San Bernardino County

Regional context, not property-specific evidence. The federal mineral resources record lists 8 workings within 5 miles of Ontario: 8 past producers. None of them still produces. What was taken out: Sand and Gravel, Construction, Gold, Gold, Silver. Distance is straight-line from the map coordinates, so a quarry counted here may appear on a neighbouring settlement's page as well.

Every working recorded in San Bernardino County

Regional context, not property-specific evidence. The National Weather Service names Ontario in 7 storm reports between 2004 and 2025: 2 flash flood, 2 flood, 2 heavy rain, 1 lightning. The reports record 3 deaths and 1 injury. Each account below is quoted exactly as the forecast office filed it, from the NOAA Storm Events Database, and each date opens the federal record of that event.

Every storm recorded in San Bernardino County

The eight closest, with where each one stands in the county. Distances are straight-line, computed from the Geographic Names Information System coordinates.

Matched on this settlement's Geographic Names Information System number rather than its name, so it cannot be a different place of the same name in another state.

This settlement is recorded in the Geographic Names Information System as feature 1652764. The sheet list is computed by point-in-boundary test against the United States Geological Survey's historical topographic inventory. Both are works of the United States government and carry no copyright under 17 U.S.C. 105.

Wildfire. Short, Karen C. 2022. Spatial wildfire occurrence data for the United States, 1992-2020 [FPA_FOD_20221014]. 6th Edition. Fort Collins, CO: Forest Service Research Data Archive. https://doi.org/10.2737/RDS-2013-0009.6 Collected with United States Government funding and usable without additional permissions or fees.

Mines and quarries. USGS Mineral Resources Data System (MRDS) https://mrdata.usgs.gov/mrds/ A work of the United States government, no copyright under 17 U.S.C. 105.

Storms. NOAA National Centers for Environmental Information, Storm Events Database https://www.ncei.noaa.gov/stormevents/ A work of the United States government, no copyright under 17 U.S.C. 105. Narratives are quoted verbatim from the National Weather Service report and are not edited or summarised.