St. Ann Highlands: Demographics & People

St. Ann Highlands's population stands at 453 people, in 179 households. Population shrank 6.2% from 483 (2022) to 453 (2024). Median age 38.1 years. Children under 18 are 28% of the population. Population is 100% White (non-Hispanic). The community is relatively homogeneous (Simpson index 0.00). 59% of households are family-led. County is losing 4,788 residents per year (2022-2023). County health: 19% adult obesity, 10% smoke.

Population & Trend

Population shrank 6.2% from 483 (2022) to 453 (2024). Estimated 2026 population: ~425 (extrapolated at -3.1%/yr trend). Census Bureau Vintage estimate: 390.

Census data vintage2024
Population330,758 people
Annual growth rate · Population change-6.2%
Annual growth rate · Population (2022)483
Annual growth rate · Population (2024)453
Annual growth rate · Trend categoryshrinking
Population453 people
Population Estimate390

Sources: Census ACS 5-Year 2023, Table B01003  ·  Refreshed 2026-04-12

Age Distribution

Median age 38.1y is 0.8 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 age38.1 years (at Colorado median)
Age Summary · Children Pct28.0%
Age Summary · Characterfamily-oriented
Population under 18127
Median age38.1 years (at Colorado median)

Sources: Census ACS 5-Year 2023  ·  Refreshed 2026-04-12

Race, Ethnicity & Diversity

Of 453 residents, race / ethnicity breaks down by Census ACS counts (a person can identify with one or more groups). The Simpson diversity index is 0.00 (0 = single group, 1 = perfectly even distribution); this is read as relatively homogeneous.

White residents483
Diversity Index · Diversity labelrelatively homogeneous
Diversity Index · Groups counted1
Diversity Index · Largest group share100.0%
White (non-Hispanic) population100.0%

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 (6)

(unnamed)
Irish
(unnamed)
German
(unnamed)
Italian
(unnamed)
American
(unnamed)
English
(unnamed)
Polish

Citizenship & Origin

Where residents were born and their citizenship status (Census ACS).

Residents born in this state167
Residents born in another state277
Share born in this state36.9%
Share born in another state63.1%
Native-born U.S. citizens61.1%
Naturalized citizens2.0%
Total foreign-born residents44
From Europe37

Households & Family Composition

179 households. Averaging 2.6 people each — matches the U.S. average of 2.5. 59% are family households — below the U.S. share of ~65%. Of 102 families, 63% are married couples with children.

Children under 18114
Total families102
Married couples with children64
Average household size2.56
Grandparents living with grandchildren1,748
Grandparents responsible for grandchildren884
Family households105 households
Households that are families58.7%
Total households179 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. 20.8% moved within the county in the past year — the U.S. baseline is roughly 8–10%. The surrounding county is losing 4,788 residents per year on net (IRS migration data).

Moved within the county (past year)20.8%
Migration · People moving in (annual)303,289
Migration · People moving out (annual)308,077
Migration · Net migration (in − out)-4,788
Migration · Year2022-2023

Sources: IRS SOI Migration 2021-2022  ·  Refreshed 2026-04-12

Other

Congressional District · District2
Congressional District · FormattedCO-02
Congressional District · Congress118th
Cdc Birth Rate · Fips8,013
Cdc Birth Rate · State Fips8
Cdc Birth Rate · County Fips13
Cdc Birth Rate · CountyBoulder
Cdc Birth Rate · Birth Rate5.3%
Cdc Birth Rate · Lower Ci4.70
Cdc Birth Rate · Upper Ci6.00
Cdc Mortality · Fips8,013
Cdc Mortality · CountyBoulder County
Cdc Mortality · Urban RuralMedium metro
Cdc Mortality · Total Deaths 2020 20239,039
Cdc Vaccination · Fips8,013
Cdc Vaccination · CountyBoulder County
Cdc Vaccination · Dose1 Pop Pct91.1%
Cdc Vaccination · Series Complete Pct82.8%
Cdc Vaccination · Booster Pct69.1%
Cdc Vaccination · Population 2019326,196
Cdc Vaccination · Metro StatusMetro
Family Score · Score10
Family Score · Schools20
Family Score · Children Pct28.0%
Family Score · Ratingexcellent
Town Summary · Key Factspopulation 453, shrinking, family-oriented, affluent, white collar
Town Summary · Population453 people
Town Summary · CountyBoulder County

Sources: Census place-to-CD118 crosswalk (place_fips) · federal dataset cascade