Discover Castalia
The U.S. Census Bureau lists Castalia city as an incorporated place. Its Vintage 2025 series estimates a resident population of 142 on July 1, 2025. In this collection, a small place means one with a 2025 estimate of 10,000 or fewer; that is a selection threshold, not a separate legal category. The figure describes the Census place geography, not everyone in a surrounding ZIP code or neighboring unincorporated area.
More about Castalia
The same series gives Castalia city a 2020 population estimate of 145. Comparing those two reference points, the estimate decreased by 3 residents, a net change of -2.1%. The comparison records endpoints only. It does not identify causes, describe seasonal variation, or predict what will happen next. The 2025 number is an estimate for its stated reference date, not a live headcount.
Within Iowa, Castalia city ranks 194 among incorporated places whose 2025 estimates are at or below 10,000, ordered from smallest upward. This is a within-state population comparison, not a ranking of quality, popularity, or amenities. For a meaningful comparison, use the same Census vintage, reference year, and geographic boundaries. The Census name is retained here so readers can distinguish the official estimate record from the postal-city label used by this directory.
Sources
- U.S. Census Bureau Vintage 2025 estimate: Castalia city: https://www2.census.gov/programs-surveys/popest/datasets/2020-2025/cities/totals/sub-est2025.csv
- U.S. Census Bureau: City and Town Population Totals, 2020-2025: https://www.census.gov/data/tables/time-series/demo/popest/2020s-total-cities-and-towns.html
