St. Charles: Demographics & People
Census counts 914 people in St. Charles, in 348 households. Population grew 2.6% from 891 (2022) to 914 (2024). Median age 36.2 years. (4.4y younger than Madison County; 2.6y younger than Iowa). Children under 18 are 22% of the population. Population is 86% White (non-Hispanic) and 10% Hispanic or Latino. The community is relatively homogeneous (Simpson index 0.10). 63% of households are family-led. County health: 38% adult obesity, 13% smoke.
- 2.6 people per household.
- 37% non-family households (singles, roommates).
Population & Trend
Population grew 2.6% from 891 (2022) to 914 (2024) — about 4.3× the recent U.S. annual rate of ~0.6%/yr. Estimated 2026 population: ~937 (extrapolated at 1.3%/yr trend). Census Bureau Vintage estimate: 969.
| Census data vintage | 2024 |
|---|---|
| Population | 16,548 people |
| Annual growth rate · Population change | 2.6% |
| Annual growth rate · Population (2022) | 891 |
| Annual growth rate · Population (2024) | 914 |
| Annual growth rate · Population growing | Yes |
| Annual growth rate · Trend category | growing |
| Population | 914 people |
| Population Estimate | 969 |
Sources: Census ACS 5-Year 2023, Table B01003 · Refreshed 2026-04-12
Age Distribution
Median age 36.2y is 2.7 years younger than the U.S. median (38.9y). Children under 18 make up 22% — near the U.S. share of ~22%.
| Age Summary · Median age | 36.2 years (vs Iowa 38.8y) |
|---|---|
| Age Summary · Children Pct | 22.1% |
| Age Summary · Character | family-oriented |
| Population under 18 | 202 |
| Median age | 36.2 years (vs Iowa 38.8y) |
Sources: Census ACS 5-Year 2023 · Refreshed 2026-04-12
Race, Ethnicity & Diversity
Of 914 residents, race / ethnicity breaks down by Census ACS counts (a person can identify with one or more groups). The Simpson diversity index is 0.10 (0 = single group, 1 = perfectly even distribution); this is read as relatively homogeneous.
| White residents | 835 |
|---|---|
| Hispanic or Latino residents | 44 |
| Diversity Index · Diversity index (Simpson) | 9.5% |
| Diversity Index · Diversity label | relatively homogeneous |
| Diversity Index · Groups counted | 2 |
| Diversity Index · Largest group share | 95.0% |
| Hispanic or Latino population | 10.4% |
| White (non-Hispanic) population | 86.5% |
Sources: Census ACS 5-Year 2023 · Refreshed 2026-04-12
Ancestry
Self-reported ancestry from Census ACS — what residents report as their ethnic origin, separate from race. Counts can exceed population because people can list multiple ancestries.
Top (7)
Citizenship & Origin
Where residents were born and their citizenship status (Census ACS). 2.0% are foreign-born — below the U.S. average of 13.9%. 6% have naturalized to U.S. citizenship.
| Residents born in this state | 697 |
|---|---|
| Residents born in another state | 146 |
| Share born in this state | 76.3% |
| Share born in another state | 23.7% |
| Native-born U.S. citizens | 16.0% |
| Foreign-born residents | 2.0% |
| Naturalized citizens | 5.8% |
| Total foreign-born residents | 48 |
Households & Family Composition
348 households. Averaging 2.8 people each — larger than the U.S. average of 2.5. 63% are family households — below the U.S. share of ~65%. Of 191 families, 31% are married couples with children.
| Children under 18 | 209 |
|---|---|
| Total families | 191 |
| Married couples with children | 60 |
| Single-parent households | 5 |
| Average household size | 2.78 |
| Women who gave birth (past year) | 15.8% |
| Grandparents living with grandchildren | 3 |
| Family households | 218 households |
| Households that are families | 62.6% |
| Total households | 348 households |
Sources: Census ACS 5-Year 2023 · Refreshed 2026-04-12
Residential Stability & Migration
How long residents have lived here and where they came from. 12.1% moved within the county in the past year — the U.S. baseline is roughly 8–10%.
| Moved within the county (past year) | 12.1% |
|---|---|
| Migration · People moving in (annual) | 16,728 |
| Migration · People moving out (annual) | 16,735 |
| Migration · Net migration (in − out) | -7 |
| Migration · Year | 2022-2023 |
Sources: IRS SOI Migration 2021-2022 · Refreshed 2026-04-12
Disability
Census ACS measures self-reported functional limitations — vision, hearing, mobility, cognitive, self-care, or independent-living. The U.S. baseline disability rate is about 12–13%; rates trend higher with median age.
| Residents with a disability | 46 |
|---|---|
| Disability rate | 5.1% |
Other
| Congressional District · District | 3 |
|---|---|
| Congressional District · Formatted | IA-03 |
| Congressional District · Congress | 118th |
| Cdc Birth Rate · Fips | 19,121 |
| Cdc Birth Rate · State Fips | 19 |
| Cdc Birth Rate · County Fips | 121 |
| Cdc Birth Rate · County | Madison |
| Cdc Birth Rate · Birth Rate | 8.3% |
| Cdc Birth Rate · Lower Ci | 5.60 |
| Cdc Birth Rate · Upper Ci | 11.90 |
| Cdc Mortality · Fips | 19,121 |
| Cdc Mortality · County | Madison County |
| Cdc Mortality · Urban Rural | Medium metro |
| Cdc Mortality · Total Deaths 2020 2023 | 388 |
| Cdc Vaccination · Fips | 19,121 |
| Cdc Vaccination · County | Madison County |
| Cdc Vaccination · Dose1 Pop Pct | 59.6% |
| Cdc Vaccination · Series Complete Pct | 55.5% |
| Cdc Vaccination · Booster Pct | 58.9% |
| Cdc Vaccination · Population 2019 | 16,338 |
| Cdc Vaccination · Metro Status | Metro |
| Family Score · Score | 6.00 |
| Family Score · Schools | 10 |
| Family Score · Children Pct | 22.1% |
| Family Score · Rating | good |
| Town Summary · Key Facts | population 914, growing, family-oriented, upper-middle, mixed |
| Town Summary · Population | 914 people |
| Town Summary · County | Madison County |
Sources: Census place-to-CD118 crosswalk (place_fips) · federal dataset cascade