St. Johns: Demographics & People
St. Johns is home to 184 people, in 92 households. Population grew 37.3% from 134 (2022) to 184 (2024). Median age 46.4 years. (4.4y older than Perry County; 7.3y older than Illinois). Children under 18 are 15% of the population. Population is 76% White (non-Hispanic) and 9% Asian. The community is relatively homogeneous (Simpson index 0.08). 53% of households are family-led. County health: 40% adult obesity, 21% smoke.
- 2.0 people per household.
- 47% non-family households (singles, roommates).
Population & Trend
Population grew 37.3% from 134 (2022) to 184 (2024) — about 62.2× the recent U.S. annual rate of ~0.6%/yr. Estimated 2026 population: ~259 (extrapolated at 18.7%/yr trend). Census Bureau Vintage estimate: 385.
| Census data vintage | 2024 |
|---|---|
| Population | 20,945 people |
| Annual growth rate · Population change | 37.3% |
| Annual growth rate · Population (2022) | 134 |
| Annual growth rate · Population (2024) | 184 |
| Annual growth rate · Population growing | Yes |
| Annual growth rate · Trend category | booming |
| Population | 184 people |
| Population Estimate | 385 |
Sources: Census ACS 5-Year 2023, Table B01003 · Refreshed 2026-04-12
Age Distribution
Median age 46.4y is 7.5 years older than the U.S. median (38.9y). Children under 18 make up 15% — below the U.S. share of ~22%.
| Age Summary · Median age | 46.4 years (vs Illinois 39.1y) |
|---|---|
| Age Summary · Children Pct | 15.2% |
| Age Summary · Character | established |
| Population under 18 | 28 |
| Median age | 46.4 years (vs Illinois 39.1y) |
Sources: Census ACS 5-Year 2023 · Refreshed 2026-04-12
Race, Ethnicity & Diversity
Of 184 residents, race / ethnicity breaks down by Census ACS counts (a person can identify with one or more groups). The Simpson diversity index is 0.08 (0 = single group, 1 = perfectly even distribution); this is read as relatively homogeneous.
| White residents | 122 |
|---|---|
| Asian residents | 4 |
| Hispanic or Latino residents | 1 |
| Diversity Index · Diversity index (Simpson) | 7.6% |
| Diversity Index · Diversity label | relatively homogeneous |
| Diversity Index · Groups counted | 3 |
| Diversity Index · Largest group share | 96.1% |
| Asian population | 9.2% |
| Hispanic or Latino population | 3.8% |
| White (non-Hispanic) population | 76.1% |
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). 2.2% are foreign-born — below the U.S. average of 13.9%. 5% have naturalized to U.S. citizenship.
| Residents born in this state | 115 |
|---|---|
| Residents born in another state | 56 |
| Share born in this state | 62.5% |
| Share born in another state | 37.5% |
| Native-born U.S. citizens | 30.4% |
| Foreign-born residents | 2.2% |
| Naturalized citizens | 4.9% |
| Total foreign-born residents | 2 |
| From Africa | 2 |
| From Latin America | 2 |
Households & Family Composition
92 households. Averaging 2.0 people each — smaller than the U.S. average of 2.5. 53% are family households — below the U.S. share of ~65%. Of 39 families, 5% are married couples with children.
| Children under 18 | 17 |
|---|---|
| Total families | 39 |
| Married couples with children | 2 |
| Single-parent households | 3 |
| Average household size | 1.97 |
| Women who gave birth (past year) | 17.6% |
| Grandparents living with grandchildren | 346 |
| Grandparents responsible for grandchildren | 97 |
| Family households | 49 households |
| Households that are families | 53.3% |
| Total households | 92 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. 8.2% moved within the county in the past year — the U.S. baseline is roughly 8–10%.
| Moved within the county (past year) | 8.2% |
|---|---|
| Migration · People moving in (annual) | 16,442 |
| Migration · People moving out (annual) | 16,472 |
| Migration · Net migration (in − out) | -30 |
| 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 | 20 |
|---|---|
| Disability rate | 11.6% |
Other
| Congressional District · District | 12 |
|---|---|
| Congressional District · Formatted | IL-12 |
| Congressional District · Congress | 118th |
| Cdc Birth Rate · Fips | 17,145 |
| Cdc Birth Rate · State Fips | 17 |
| Cdc Birth Rate · County Fips | 145 |
| Cdc Birth Rate · County | Perry |
| Cdc Birth Rate · Birth Rate | 24.3% |
| Cdc Birth Rate · Lower Ci | 18.80 |
| Cdc Birth Rate · Upper Ci | 30.80 |
| Cdc Mortality · Fips | 17,145 |
| Cdc Mortality · County | Perry County |
| Cdc Mortality · Urban Rural | Noncore |
| Cdc Mortality · Total Deaths 2020 2023 | 757 |
| Cdc Vaccination · Fips | 17,145 |
| Cdc Vaccination · County | Perry County |
| Cdc Vaccination · Dose1 Pop Pct | 56.5% |
| Cdc Vaccination · Series Complete Pct | 51.6% |
| Cdc Vaccination · Booster Pct | 52.0% |
| Cdc Vaccination · Population 2019 | 20,916 |
| Cdc Vaccination · Metro Status | Non-metro |
| Family Score · Score | 6.50 |
| Family Score · Schools | 11 |
| Family Score · Children Pct | 15.2% |
| Family Score · Rating | good |
| Town Summary · Key Facts | population 184, booming, established, middle-class, mixed |
| Town Summary · Population | 184 people |
| Town Summary · County | Perry County |
Sources: Census place-to-CD118 crosswalk (place_fips) · federal dataset cascade