Mason City, Illinois

Mason City fell from 2,343 to 2,077 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.

• 1948 USGS Mason City quadrangle1:62500, 2 printings
• 1949 USGS Mason City quadrangle1:62500, 2 printings
• 1958 USGS Peoria quadrangle1:250000, 4 printings
• 1961 USGS Peoria quadrangle1:250000
• 1963 USGS Peoria quadrangle1:250000
• 1980 USGS Mason City quadrangle1:24000
• 1985 USGS Lincoln quadrangle1:100000
• 1989 USGS Lincoln quadrangle1:100000
• 1990 USGS Peoria quadrangle1:250000

Regional context, not property-specific evidence. The federal mineral resources record lists 3 workings within 5 miles of Mason City: 2 producers, 1 past producer. 2 still produce. What was taken out: Sand and Gravel, Construction. 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 Mason County

Regional context, not property-specific evidence. The National Weather Service names Mason City in 24 storm reports between 1995 and 2025: 15 thunderstorm wind, 5 hail, 3 tornado, 1 flash flood. No death or injury is recorded in these reports. 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 Mason 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 413098. 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.