Rosemont: Demographics & People
Census counts 3,421 people in Rosemont, in 1,381 households. Population shrank 8.1% from 3,722 (2022) to 3,421 (2024). Median age 38.5 years. (2.7y younger than Montgomery County; 1.7y older than Pennsylvania). Children under 18 are 19% of the population. Population is 70% White (non-Hispanic) and 10% Asian. 43% of households are family-led. County is losing 6,493 residents per year (2022-2023). County health: 31% adult obesity, 13% smoke.
- 2.5 people per household (vs Pennsylvania avg 2.4).
- 57% non-family households (singles, roommates) (vs Pennsylvania 44%).
- 68 dependents per 100 working-age (youth + seniors / 18-64) (vs Pennsylvania 66).
Population & Trend
Population shrank 8.1% from 3,722 (2022) to 3,421 (2024). Estimated 2026 population: ~3,149 (extrapolated at -4.0%/yr trend). Census Bureau Vintage estimate: 2,809.
| Census data vintage | 2024 |
|---|---|
| Population | 576,830 people |
| Annual growth rate · Population change | -8.1% |
| Annual growth rate · Population (2022) | 3,722 |
| Annual growth rate · Population (2024) | 3,421 |
| Annual growth rate · Trend category | shrinking |
| Population | 3,421 people (vs Pennsylvania 12,317) |
| Population Estimate | 2,809 |
Sources: Census ACS 5-Year 2023, Table B01003 · Refreshed 2026-04-12
Age Distribution
Median age 38.5y is 0.4 years younger than the U.S. median (38.9y). Children under 18 make up 19% — below the U.S. share of ~22%.
| Age Summary · Median age | 38.5 years (vs Pennsylvania 36.8y) |
|---|---|
| Age Summary · Children Pct | 18.6% |
| Age Summary · Character | family-oriented |
| Age Summary · Total Pop | 3,421 |
| Age Summary · Under 18 | 635 |
| Age Summary · 18 To 34 | 914.0× |
| Age Summary · 35 To 64 | 1,126.0× |
| Age Summary · 65 Plus | 746 |
| Population under 18 | 635 |
| Median age | 38.5 years (vs Pennsylvania 36.8y) |
Sources: Census ACS 5-Year 2024 — place-level B01001 query · Census ACS 5-Year 2023 · Refreshed 2026-04-29
Race, Ethnicity & Diversity
Of 3,421 residents, race / ethnicity breaks down by Census ACS counts (a person can identify with one or more groups).
| White residents | 2,815 |
|---|---|
| Black residents | 115 |
| Asian residents | 403 |
| Hispanic or Latino residents | 262 |
| Diversity Index · Simpson Index | 30.2% |
| Diversity Index · Interpretation | less diverse |
| Asian population | 10.3% (vs Pennsylvania 2.5%) |
| Black population | 3.6% (vs Pennsylvania 7.7%) |
| Hispanic or Latino population | 8.1% (at Pennsylvania median) |
| White (non-Hispanic) population | 69.9% (vs Pennsylvania 71.2%) |
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). 2.8% are foreign-born — below the U.S. average of 13.9%. 13% have naturalized to U.S. citizenship.
| Residents born in this state | 1,487 |
|---|---|
| Residents born in another state | 1,409 |
| Share born in this state | 43.5% |
| Share born in another state | 56.5% |
| Native-born U.S. citizens | 41.2% |
| Foreign-born residents | 2.8% |
| Naturalized citizens | 12.6% |
| Total foreign-born residents | 548 |
| From Europe | 105 |
| From Africa | 340 |
| From Latin America | 11 |
Households & Family Composition
1,381 households. Averaging 2.1 people each — smaller than the U.S. average of 2.5. 43% are family households — below the U.S. share of ~65%. Of 707 families, 49% are married couples with children.
| Children under 18 | 703 |
|---|---|
| Total families | 707 |
| Married couples with children | 346 |
| Average household size | 2.15 |
| Women who gave birth (past year) | 13.3% |
| Grandparents living with grandchildren | 9 |
| Grandparents responsible for grandchildren | 9 |
| Family households | 588 households (vs Pennsylvania 2,885) |
| Households that are families | 42.6% (vs Pennsylvania 55.6%) |
| Total households | 1,381 households (vs Pennsylvania 5,038) |
Sources: Census ACS 5-Year 2023 · Refreshed 2026-04-12
Residential Stability & Migration
How long residents have lived here and where they came from. 17.2% moved within the county in the past year — the U.S. baseline is roughly 8–10%. The surrounding county is losing 6,493 residents per year on net (IRS migration data).
| Moved within the county (past year) | 17.2% |
|---|---|
| Migration · People moving in (annual) | 514,150 |
| Migration · People moving out (annual) | 520,643 |
| Migration · Net migration (in − out) | -6,493 |
| 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 | 176 |
|---|---|
| Disability rate | 4.7% |
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. 500 residents live in group quarters (14.6% of population).
| Living in group quarters | 500 |
|---|
Other
| Congressional District · District | 4 |
|---|---|
| Congressional District · Congress | 118th |
| Cdc Birth Rate · Fips | 42045 |
| Cdc Birth Rate · State Fips | 42 |
| Cdc Birth Rate · County Fips | 045 |
| Cdc Birth Rate · County | Delaware |
| Cdc Birth Rate · Birth Rate | 9.8% |
| Cdc Birth Rate · Lower Ci | 9.10 |
| Cdc Birth Rate · Upper Ci | 10.50 |
| Cdc Mortality · Fips | 42045 |
| Cdc Mortality · County | Delaware County |
| Cdc Mortality · Urban Rural | Large fringe metro |
| Cdc Mortality · Total Deaths 2020 2023 | 18,487 |
| Cdc Vaccination · Fips | 42045 |
| Cdc Vaccination · County | Delaware County |
| Cdc Vaccination · Dose1 Pop Pct | 95.0% |
| Cdc Vaccination · Series Complete Pct | 83.4% |
| Cdc Vaccination · Booster Pct | 44.1% |
| Cdc Vaccination · Population 2019 | 566,747 |
| Cdc Vaccination · Metro Status | Metro |
| Family Score · Score | 1.50 |
| Family Score · Schools | 1 |
| Family Score · Children Pct | 18.6% |
| Family Score · Rating | limited |
| Town Summary · Key Facts | population 3,421, shrinking, family-oriented, upper-middle, white collar |
| Town Summary · Population | 3,421 people (vs Pennsylvania 12,317) |
| Town Summary · County | Delaware County |
Sources: NCES school congressional district assignment · federal dataset cascade