Algonquin: Demographics & People
About 30,067 people live in Algonquin, in 10,968 households. Population grew 0.6% from 29,904 (2022) to 30,067 (2024). Median age 41.4 years. (0.7y older than McHenry County; 3.7y older than Illinois). Children under 18 are 21% of the population. Population is 73% White (non-Hispanic) and 16% Hispanic or Latino. The community is somewhat diverse (Simpson index 0.36). 78% of households are family-led. County is losing 3,975 residents per year (2022-2023). County health: 37% adult obesity, 12% smoke.
- 2.7 people per household (vs Illinois avg 2.5).
- 22% non-family households (singles, roommates) (vs Illinois 38%).
- 56 dependents per 100 working-age (youth + seniors / 18-64) (vs Illinois 64).
Population & Trend
Population grew 0.6% from 29,904 (2022) to 30,067 (2024) — close to the U.S. annual rate of ~0.6%/yr. Estimated 2026 population: ~30,232 (extrapolated at 0.3%/yr trend). Census Bureau Vintage estimate: 30,455.
| Census data vintage | 2024 |
|---|---|
| Population | 516,522 people |
| Annual growth rate · Population change | 0.6% |
| Annual growth rate · Population (2022) | 29,904 |
| Annual growth rate · Population (2024) | 30,067 |
| Annual growth rate · Population growing | Yes |
| Annual growth rate · Trend category | stable |
| Population | 30,067 people (vs Illinois 39,460) |
| Population Estimate | 30,455 |
Sources: Census ACS 5-Year 2023, Table B01003 · Refreshed 2026-04-12
Age Distribution
Median age 41.4y is 2.5 years older than the U.S. median (38.9y). Children under 18 make up 21% — below the U.S. share of ~22%.
| Age Summary · Median age | 41.4 years (vs Illinois 37.7y) |
|---|---|
| Age Summary · Children Pct | 20.8% |
| Age Summary · Character | established |
| Age Summary · Total Pop | 30,067 |
| Age Summary · Under 18 | 6,252 |
| Age Summary · 18 To 34 | 6,401.0× |
| Age Summary · 35 To 64 | 12,912.0× |
| Age Summary · 65 Plus | 4,502 |
| Population under 18 | 6,252 |
| Median age | 41.4 years (vs Illinois 37.7y) |
Sources: Census ACS 5-Year 2024 — place-level B01001 query · Census ACS 5-Year 2023 · Refreshed 2026-04-29
Race, Ethnicity & Diversity
Of 30,067 residents, race / ethnicity breaks down by Census ACS counts (a person can identify with one or more groups). The Simpson diversity index is 0.36 (0 = single group, 1 = perfectly even distribution); this is read as somewhat diverse.
| White residents | 23,756 |
|---|---|
| Black residents | 666 |
| Asian residents | 1,671 |
| Hispanic or Latino residents | 4,240 |
| Diversity Index · Diversity index (Simpson) | 36.4% |
| Diversity Index · Diversity label | somewhat diverse |
| Diversity Index · Groups counted | 4 |
| Diversity Index · Largest group share | 78.3% |
| Asian population | 5.3% (vs Illinois 6.1%) |
| Black population | 2.8% (vs Illinois 9.3%) |
| Hispanic or Latino population | 15.6% (vs Illinois 17.6%) |
| White (non-Hispanic) population | 72.7% (vs Illinois 54.8%) |
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). 1.0% are foreign-born — below the U.S. average of 13.9%. 12% have naturalized to U.S. citizenship.
| Residents born in this state | 21,450 |
|---|---|
| Residents born in another state | 4,636 |
| Share born in this state | 71.3% |
| Share born in another state | 28.7% |
| Native-born U.S. citizens | 15.4% |
| Foreign-born residents | 1.0% |
| Naturalized citizens | 12.3% |
| Total foreign-born residents | 3,467 |
| From Europe | 1,327 |
| From Africa | 1,018 |
| From Latin America | 121 |
Households & Family Composition
10,968 households. Averaging 2.7 people each — larger than the U.S. average of 2.5. 78% are family households — above the U.S. share of ~65%. Of 8,573 families, 31% are married couples with children.
| Children under 18 | 6,278 |
|---|---|
| Total families | 8,573 |
| Married couples with children | 2,659 |
| Single-parent households | 293 |
| Average household size | 2.74 |
| Women who gave birth (past year) | 10.1% |
| Grandparents living with grandchildren | 288 |
| Grandparents responsible for grandchildren | 112 |
| Family households | 8,561 households (vs Illinois 9,709) |
| Households that are families | 78.1% (vs Illinois 62.4%) |
| Total households | 10,968 households (vs Illinois 14,867) |
Sources: Census ACS 5-Year 2023 · Refreshed 2026-04-12
Residential Stability & Migration
How long residents have lived here and where they came from. 7.9% moved within the county in the past year — the U.S. baseline is roughly 8–10%. The surrounding county is losing 3,975 residents per year on net (IRS migration data).
| Moved within the county (past year) | 7.9% |
|---|---|
| Migration · People moving in (annual) | 503,069 |
| Migration · People moving out (annual) | 507,044 |
| Migration · Net migration (in − out) | -3,975 |
| 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 | 1,157 |
|---|---|
| Disability rate | 3.9% |
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. 5 residents live in group quarters (0.0% of population).
| Living in group quarters | 5 |
|---|
Other
| Congressional District · District | 6 |
|---|---|
| Congressional District · Congress | 118th |
| Cdc Birth Rate · Fips | 17089 |
| Cdc Birth Rate · State Fips | 17 |
| Cdc Birth Rate · County Fips | 089 |
| Cdc Birth Rate · County | Kane |
| Cdc Birth Rate · Birth Rate | 13.8% |
| Cdc Birth Rate · Lower Ci | 12.90 |
| Cdc Birth Rate · Upper Ci | 14.70 |
| Cdc Mortality · Fips | 17089 |
| Cdc Mortality · County | Kane County |
| Cdc Mortality · Urban Rural | Large fringe metro |
| Cdc Mortality · Total Deaths 2020 2023 | 13,660 |
| Cdc Vaccination · Fips | 17089 |
| Cdc Vaccination · County | Kane County |
| Cdc Vaccination · Dose1 Pop Pct | 74.8% |
| Cdc Vaccination · Series Complete Pct | 69.1% |
| Cdc Vaccination · Booster Pct | 56.0% |
| Cdc Vaccination · Population 2019 | 532,403 |
| Cdc Vaccination · Metro Status | Metro |
| Family Score · Score | 9.10 |
| Family Score · Schools | 12 |
| Family Score · Childcare Centers | 7 |
| Family Score · Children Pct | 20.8% |
| Family Score · Rating | excellent |
| Town Summary · Key Facts | population 30,067, stable, established, affluent, white collar |
| Town Summary · Population | 30,067 people (vs Illinois 39,460) |
| Town Summary · County | Kane County |
Sources: NCES school congressional district assignment · federal dataset cascade