St. Ignatius: Demographics & People
St. Ignatius is home to 977 people, in 334 households. Population shrank 7.2% from 1,053 (2022) to 977 (2024). Median age 31.0 years. (13.3y younger than Lake County; 9.8y younger than Montana). Children under 18 are 32% of the population. Population is 54% White (non-Hispanic) and 4% Hispanic or Latino. The community is relatively homogeneous (Simpson index 0.10). 55% of households are family-led. County is gaining 1,508 residents per year (2022-2023). County health: 34% adult obesity, 19% smoke.
- 2.9 people per household.
- 45% non-family households (singles, roommates).
Population & Trend
Population shrank 7.2% from 1,053 (2022) to 977 (2024). Estimated 2026 population: ~907 (extrapolated at -3.6%/yr trend). Census Bureau Vintage estimate: 820.
| Census data vintage | 2024 |
|---|---|
| Population | 31,134 people |
| Annual growth rate · Population change | -7.2% |
| Annual growth rate · Population (2022) | 1,053 |
| Annual growth rate · Population (2024) | 977 |
| Annual growth rate · Trend category | shrinking |
| Population | 977 people |
| Population Estimate | 820 |
Sources: Census ACS 5-Year 2023, Table B01003 · Refreshed 2026-04-12
Age Distribution
Median age 31.0y is 7.9 years younger than the U.S. median (38.9y). Children under 18 make up 32% — above the U.S. share of ~22%.
| Age Summary · Median age | 31.0 years (vs Montana 40.8y) |
|---|---|
| Age Summary · Children Pct | 32.3% |
| Age Summary · Character | young professional |
| Population under 18 | 316 |
| Median age | 31.0 years (vs Montana 40.8y) |
Sources: Census ACS 5-Year 2023 · Refreshed 2026-04-12
Race, Ethnicity & Diversity
Of 977 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 | 581 |
|---|---|
| Hispanic or Latino residents | 32 |
| Diversity Index · Diversity index (Simpson) | 9.9% |
| Diversity Index · Diversity label | relatively homogeneous |
| Diversity Index · Groups counted | 2 |
| Diversity Index · Largest group share | 94.8% |
| Asian population | 0.2% |
| Hispanic or Latino population | 3.5% |
| White (non-Hispanic) population | 53.9% |
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). 0.3% are foreign-born — below the U.S. average of 13.9%. 1% have naturalized to U.S. citizenship.
| Residents born in this state | 660 |
|---|---|
| Residents born in another state | 305 |
| Share born in this state | 67.6% |
| Share born in another state | 32.4% |
| Native-born U.S. citizens | 31.2% |
| Foreign-born residents | 0.3% |
| Naturalized citizens | 0.9% |
| Total foreign-born residents | 6 |
Households & Family Composition
334 households. Averaging 3.2 people each — larger than the U.S. average of 2.5. 55% are family households — below the U.S. share of ~65%. Of 195 families, 26% are married couples with children.
| Children under 18 | 384 |
|---|---|
| Total families | 195 |
| Married couples with children | 51 |
| Single-parent households | 17 |
| Average household size | 3.24 |
| Women who gave birth (past year) | 17.5% |
| Grandparents living with grandchildren | 40 |
| Grandparents responsible for grandchildren | 14 |
| Family households | 183 households |
| Households that are families | 54.8% |
| Total households | 334 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. 11.7% moved within the county in the past year — the U.S. baseline is roughly 8–10%. The surrounding county is gaining 1,508 residents per year on net (IRS migration data).
| Moved within the county (past year) | 11.7% |
|---|---|
| Migration · People moving in (annual) | 28,960 |
| Migration · People moving out (annual) | 27,452 |
| Migration · Net migration (in − out) | 1,508 |
| Migration · Population growing | Yes |
| 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 | 99 |
|---|---|
| Disability rate | 9.7% |
Other
| Congressional District · District | 1 |
|---|---|
| Congressional District · Formatted | MT-01 |
| Congressional District · Congress | 118th |
| Cdc Birth Rate · Fips | 30,047 |
| Cdc Birth Rate · State Fips | 30 |
| Cdc Birth Rate · County Fips | 47 |
| Cdc Birth Rate · County | Lake |
| Cdc Birth Rate · Birth Rate | 27.4% |
| Cdc Birth Rate · Lower Ci | 22.80 |
| Cdc Birth Rate · Upper Ci | 32.70 |
| Cdc Mortality · Fips | 30,047 |
| Cdc Mortality · County | Lake County |
| Cdc Mortality · Urban Rural | Noncore |
| Cdc Mortality · Total Deaths 2020 2023 | 1,001 |
| Cdc Vaccination · Fips | 30,047 |
| Cdc Vaccination · County | Lake County |
| Cdc Vaccination · Dose1 Pop Pct | 67.4% |
| Cdc Vaccination · Series Complete Pct | 59.3% |
| Cdc Vaccination · Booster Pct | 55.9% |
| Cdc Vaccination · Population 2019 | 30,458 |
| Cdc Vaccination · Metro Status | Non-metro |
| Family Score · Score | 9.50 |
| Family Score · Schools | 17 |
| Family Score · Children Pct | 32.3% |
| Family Score · Rating | excellent |
| Town Summary · Key Facts | population 977, shrinking, young professional, working-class, mixed |
| Town Summary · Population | 977 people |
| Town Summary · County | Lake County |
Sources: Census place-to-CD118 crosswalk (place_fips) · federal dataset cascade