Mechanicsville: Demographics & People
Mechanicsville's population stands at 1,395 people, in 515 households. Population shrank 8.3% from 1,521 (2022) to 1,395 (2024). Median age 39.9 years. (2.7y older than St. Mary's County; 0.6y older than Maryland). Children under 18 are 32% of the population. Population is 93% White (non-Hispanic) and 3% Hispanic or Latino. The community is relatively homogeneous (Simpson index 0.11). 63% of households are family-led. County health: 35% adult obesity, 13% smoke.
- 2.7 people per household.
- 37% non-family households (singles, roommates).
Population & Trend
Population shrank 8.3% from 1,521 (2022) to 1,395 (2024). Estimated 2026 population: ~1,281 (extrapolated at -4.1%/yr trend). Census Bureau Vintage estimate: 1,140.
| Census data vintage | 2024 |
|---|---|
| Population | 113,777 people |
| Annual growth rate · Population change | -8.3% |
| Annual growth rate · Population (2022) | 1,521 |
| Annual growth rate · Population (2024) | 1,395 |
| Annual growth rate · Trend category | shrinking |
| Population | 1,395 people |
| Population Estimate | 1,140 |
Sources: Census ACS 5-Year 2023, Table B01003 · Refreshed 2026-04-12
Age Distribution
Median age 39.9y is 1.0 years older than the U.S. median (38.9y). Children under 18 make up 32% — above the U.S. share of ~22%.
| Age Summary · Median age | 39.9 years (vs Maryland 39.3y) |
|---|---|
| Age Summary · Children Pct | 32.5% |
| Age Summary · Character | family-oriented |
| Population under 18 | 453 |
| Median age | 39.9 years (vs Maryland 39.3y) |
Sources: Census ACS 5-Year 2023 · Refreshed 2026-04-12
Race, Ethnicity & Diversity
Of 1,395 residents, race / ethnicity breaks down by Census ACS counts (a person can identify with one or more groups). The Simpson diversity index is 0.11 (0 = single group, 1 = perfectly even distribution); this is read as relatively homogeneous.
| White residents | 1,420 |
|---|---|
| Black residents | 40 |
| Hispanic or Latino residents | 43 |
| Diversity Index · Diversity index (Simpson) | 10.6% |
| Diversity Index · Diversity label | relatively homogeneous |
| Diversity Index · Groups counted | 3 |
| Diversity Index · Largest group share | 94.5% |
| Black population | 2.9% |
| Hispanic or Latino population | 3.3% |
| White (non-Hispanic) population | 92.8% |
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). 1.3% are foreign-born — below the U.S. average of 13.9%.
| Residents born in this state | 682 |
|---|---|
| Residents born in another state | 695 |
| Share born in this state | 48.9% |
| Share born in another state | 51.1% |
| Native-born U.S. citizens | 49.8% |
| Foreign-born residents | 1.3% |
| Total foreign-born residents | 5,713 |
Households & Family Composition
515 households. Averaging 2.7 people each — larger than the U.S. average of 2.5. 63% are family households — near the U.S. share of ~65%. Of 386 families, 51% are married couples with children.
| Children under 18 | 472 |
|---|---|
| Total families | 386 |
| Married couples with children | 195 |
| Single-parent households | 27 |
| Average household size | 2.69 |
| Women who gave birth (past year) | 8.2% |
| Grandparents living with grandchildren | 1,861 |
| Grandparents responsible for grandchildren | 953 |
| Family households | 325 households |
| Households that are families | 63.1% |
| Total households | 515 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. 21.2% moved within the county in the past year — the U.S. baseline is roughly 8–10%.
| Moved within the county (past year) | 21.2% |
|---|---|
| Migration · People moving in (annual) | 112,262 |
| Migration · People moving out (annual) | 112,232 |
| Migration · Net migration (in − out) | 30 |
| 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 | 114 |
|---|---|
| Disability rate | 6.6% |
Other
| Congressional District · District | 5 |
|---|---|
| Congressional District · Congress | 118th |
| Cdc Birth Rate · Fips | 24,037 |
| Cdc Birth Rate · State Fips | 24 |
| Cdc Birth Rate · County Fips | 37 |
| Cdc Birth Rate · County | St Marys |
| Cdc Birth Rate · Birth Rate | 10.7% |
| Cdc Birth Rate · Lower Ci | 9.20 |
| Cdc Birth Rate · Upper Ci | 12.30 |
| Cdc Mortality · Fips | 24,037 |
| Cdc Mortality · County | St. Mary's County |
| Cdc Mortality · Urban Rural | Small metro |
| Cdc Mortality · Total Deaths 2020 2023 | 3,099 |
| Cdc Vaccination · Fips | 24,037 |
| Cdc Vaccination · County | St. Mary's County |
| Cdc Vaccination · Dose1 Pop Pct | 77.8% |
| Cdc Vaccination · Series Complete Pct | 68.9% |
| Cdc Vaccination · Booster Pct | 51.5% |
| Cdc Vaccination · Population 2019 | 113,510 |
| Cdc Vaccination · Metro Status | Metro |
| Family Score · Score | 5.90 |
| Family Score · Schools | 5 |
| Family Score · Childcare Centers | 8 |
| Family Score · Children Pct | 32.5% |
| Family Score · Rating | good |
| Town Summary · Key Facts | population 1,395, shrinking, family-oriented, affluent, white collar |
| Town Summary · Population | 1,395 people |
| Town Summary · County | St. Mary's County |
Sources: NCES school congressional district assignment · federal dataset cascade