St. Joseph: Demographics & People
St. Joseph's population stands at 3,778 people, in 1,462 households. Population shrank 1.4% from 3,833 (2022) to 3,778 (2024). Median age 37.9 years. (7.2y older than Champaign County; 1.2y younger than Illinois). Children under 18 are 28% of the population. Population is 92% White (non-Hispanic) and 4% Hispanic or Latino. The community is relatively homogeneous (Simpson index 0.07). 61% of households are family-led. County is losing 6,912 residents per year (2022-2023). County health: 36% adult obesity, 16% smoke.
- 2.6 people per household.
- 39% non-family households (singles, roommates).
Population & Trend
Population shrank 1.4% from 3,833 (2022) to 3,778 (2024). Estimated 2026 population: ~3,724 (extrapolated at -0.7%/yr trend). Census Bureau Vintage estimate: 3,653.
| Census data vintage | 2024 |
|---|---|
| Population | 205,865 people |
| Annual growth rate · Population change | -1.4% |
| Annual growth rate · Population (2022) | 3,833 |
| Annual growth rate · Population (2024) | 3,778 |
| Annual growth rate · Trend category | declining |
| Population | 3,778 people |
| Population Estimate | 3,653 |
Sources: Census ACS 5-Year 2023, Table B01003 · Refreshed 2026-04-12
Age Distribution
Median age 37.9y is 1.0 years younger than the U.S. median (38.9y). Children under 18 make up 28% — above the U.S. share of ~22%.
| Age Summary · Median age | 37.9 years (vs Illinois 39.1y) |
|---|---|
| Age Summary · Children Pct | 28.3% |
| Age Summary · Character | family-oriented |
| Population under 18 | 1,069 |
| Median age | 37.9 years (vs Illinois 39.1y) |
Sources: Census ACS 5-Year 2023 · Refreshed 2026-04-12
Race, Ethnicity & Diversity
Of 3,778 residents, race / ethnicity breaks down by Census ACS counts (a person can identify with one or more groups). The Simpson diversity index is 0.07 (0 = single group, 1 = perfectly even distribution); this is read as relatively homogeneous.
| White residents | 3,570 |
|---|---|
| Black residents | 2 |
| Asian residents | 79 |
| Hispanic or Latino residents | 62 |
| Diversity Index · Diversity index (Simpson) | 7.5% |
| Diversity Index · Diversity label | relatively homogeneous |
| Diversity Index · Groups counted | 4 |
| Diversity Index · Largest group share | 96.1% |
| Asian population | 1.6% |
| Hispanic or Latino population | 3.7% |
| White (non-Hispanic) population | 91.9% |
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 (8)
Citizenship & Origin
Where residents were born and their citizenship status (Census ACS). 1.7% are foreign-born — below the U.S. average of 13.9%. 2% have naturalized to U.S. citizenship.
| Residents born in this state | 3,341 |
|---|---|
| Residents born in another state | 298 |
| Share born in this state | 88.4% |
| Share born in another state | 11.6% |
| Native-born U.S. citizens | 7.9% |
| Foreign-born residents | 1.7% |
| Naturalized citizens | 2.0% |
| Total foreign-born residents | 76 |
| From Europe | 16 |
| From Africa | 60 |
Households & Family Composition
1,462 households. Averaging 2.5 people each — matches the U.S. average of 2.5. 61% are family households — below the U.S. share of ~65%. Of 914 families, 47% are married couples with children.
| Children under 18 | 1,000 |
|---|---|
| Total families | 914 |
| Married couples with children | 426 |
| Average household size | 2.54 |
| Women who gave birth (past year) | 12.1% |
| Grandparents living with grandchildren | 1,573 |
| Grandparents responsible for grandchildren | 727 |
| Family households | 893 households |
| Households that are families | 61.1% |
| Total households | 1,462 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. 5.9% moved within the county in the past year — the U.S. baseline is roughly 8–10%. The surrounding county is losing 6,912 residents per year on net (IRS migration data).
| Moved within the county (past year) | 5.9% |
|---|---|
| Migration · People moving in (annual) | 161,950 |
| Migration · People moving out (annual) | 168,862 |
| Migration · Net migration (in − out) | -6,912 |
| 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 | 275 |
|---|---|
| Disability rate | 7.0% |
Group Quarters
Group quarters are non-household living arrangements counted by the Census — college dormitories, nursing homes, military barracks, group homes, correctional facilities, and similar institutional or shared housing. 8 residents live in group quarters (0.2% of population).
| Living in group quarters | 8 |
|---|
Other
| Congressional District · District | 15 |
|---|---|
| Congressional District · Formatted | IL-15 |
| Congressional District · Congress | 118th |
| Cdc Birth Rate · Fips | 17,019 |
| Cdc Birth Rate · State Fips | 17 |
| Cdc Birth Rate · County Fips | 19 |
| Cdc Birth Rate · County | Champaign |
| Cdc Birth Rate · Birth Rate | 11.4% |
| Cdc Birth Rate · Lower Ci | 10.40 |
| Cdc Birth Rate · Upper Ci | 12.50 |
| Cdc Mortality · Fips | 17,019 |
| Cdc Mortality · County | Champaign County |
| Cdc Mortality · Urban Rural | Small metro |
| Cdc Mortality · Total Deaths 2020 2023 | 7,236 |
| Cdc Vaccination · Fips | 17,019 |
| Cdc Vaccination · County | Champaign County |
| Cdc Vaccination · Dose1 Pop Pct | 76.0% |
| Cdc Vaccination · Series Complete Pct | 68.3% |
| Cdc Vaccination · Booster Pct | 62.3% |
| Cdc Vaccination · Population 2019 | 209,689 |
| Cdc Vaccination · Metro Status | Metro |
| Family Score · Score | 10 |
| Family Score · Schools | 20 |
| Family Score · Children Pct | 28.3% |
| Family Score · Rating | excellent |
| Town Summary · Key Facts | population 3,778, declining, family-oriented, affluent, white collar |
| Town Summary · Population | 3,778 people |
| Town Summary · County | Champaign County |
Sources: Census place-to-CD118 crosswalk (place_fips) · federal dataset cascade