O'Fallon, Illinois

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 2 records

• Scott Field Historic Districtlisted 1994
• Tiedemann Houselisted 2020

O'Fallon grew from 28,281 to 32,289 between 2010 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.

• 1907 USGS Belleville quadrangle1:62500, 3 printings
• 1937 USGS O'Fallon quadrangle1:24000, 2 printings
• 1954 USGS O'Fallon quadrangle1:24000, 4 printings
• 1958 USGS Belleville quadrangle1:250000, 3 printings
• 1962 USGS Belleville quadrangle1:250000
• 1985 USGS Carlyle Lake quadrangle1:100000, 2 printings
• 1991 USGS O'Fallon quadrangle1:24000, 2 printings

History of St. Clair County, Illinois. With Illustrations ... and Biographical Sketches of Some of Its Prominent Men and Pioneers, published 1881 names this settlement in its chapter on O'Fallon Township. These are the passages that mention it, exactly as the scans read.

Regional context, not property-specific evidence. The federal mineral resources record lists 3 workings within 5 miles of O'Fallon: 1 past producer, 1 prospect, 1 occurrence. None of them still produces. What was taken out: Clay, Stone, Crushed/Broken. 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 St. Clair County

Regional context, not property-specific evidence. The National Weather Service names O'Fallon in 31 storm reports between 1995 and 2025: 17 thunderstorm wind, 13 hail, 1 tornado. The reports record 2 injuries. 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 St. Clair 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 426448. 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.

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.