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South Australia · Postcode 5042
St Marys postcode and suburb data
South Australia · Phone area code 08 · 9 km from Adelaide
Suburb snapshot
St Marys at a glance vs SA
Fast facts and benchmark bars show the suburb's key postcode, Census, SEIFA, school and LGA signals in context.
Quick facts
Benchmarks against SA
Income, rent and SEIFA figures are from the ABS 2021 Census and are reported in 2021 dollars, not adjusted for subsequent inflation.
Detailed comparison table
St Marys vs the SA average and the national average, using population-weighted 2021 Census data.
| Metric | St Marys | SA avg | AU avg | Greater Adelaide |
|---|---|---|---|---|
| Household income/wk | $1,490 ≈SA | $1,545 | $1,836 | $1,620 |
| Rent/wk | $285 ≈SA | $308 | $390 | $329 |
| Mortgage/month | $1,654 ≈SA | $1,558 | $1,958 | $1,666 |
| Median age | 35 | 45.0 | 45.0 | 42.0 |
| SEIFA decile | 6/10 ≈SA | 5.0/10 | 6.0/10 | 7.0/10 |
| Unemployment | 6.2% ≈SA | 6.0% | 5.0% | 6.0% |
Green pill = at least 10% above the SA average; red = at least 10% below; grey = within 10%. For unemployment, colour polarity is inverted: lower is better.
St Marys is a coastal suburb of Adelaide in South Australia, with postcode 5042. It sits about 9 km from the Adelaide CBD, within the Mitcham local government area. The suburb footprint covers roughly 1.8 square kilometres.
According to the 2021 Census, St Marys has a population of 3,010 with a median age of 35. The median weekly household income is $1,490, close to the SA average. The unemployment rate is 6.2%. The Indigenous population is 35 (1.2% of residents).
Housing in St Marys includes a median weekly rent of $285, median monthly mortgage repayment of $1,654, with 1,244 total dwellings. Owner-occupied dwellings (owned or mortgaged) make up 63.5% of housing.
On the SEIFA Index of Relative Socio-economic Advantage and Disadvantage, St Marys scores in decile 6 out of 10, which is around the national average.
St Marys is served by St Bernadette's School.
St Marys is part of the Mitcham statistical area in South Australia.
St Marys details
Location, Census, housing, SEIFA and geography fields used across this profile.
| Postcode | 5042 |
| State | South Australia (SA) |
| Phone Area Code | 08 |
| Population (2021) | 3,010 |
| Median Age | 35 years |
| Median Household Income (Census 2021) | $1,490/week |
| Median Personal Income (Census 2021) | $785/week |
| Median Weekly Rent (Census 2021) | $285 |
| Median Monthly Mortgage (Census 2021) | $1,654 |
| Average Household Size | 2.4 persons |
| Area | 1.8 km² |
| Population Density | 1643/km² |
| Total Dwellings | 1,244 |
| Australian Citizens | 80.6% |
| Indigenous Population | 35 (1.2%) |
| Unemployment Rate | 6.2% |
| SEIFA IRSAD Decile | 6/10 (average) |
| Latitude | -35.006 |
| Longitude | 138.577 |
| Distance from Adelaide | 9 km |
| Region (SA4) | Adelaide - South |
| Area (SA3) | Mitcham |
| Local Government | Mitcham |
| Federal Electorate | Boothby |
| State Electorate | Elder |
| Time Zone | ACST (UTC+9:30), Australia/Adelaide (standard time) |
Age Profile
Show counts
| 0–14 years | 498 (16.5%) |
| 15–24 years | 351 (11.7%) |
| 25–44 years | 1,124 (37.3%) |
| 45–64 years | 649 (21.6%) |
| 65+ years | 392 (13.0%) |
Housing Tenure
SEIFA socio-economic index
Health Conditions (2021 Census)
| Asthma | 225 (7.5%) |
| Arthritis | 196 (6.5%) |
| Diabetes | 143 (4.8%) |
| Heart Disease | 104 (3.5%) |
| Cancer | 64 (2.1%) |
| Lung Condition | 36 (1.2%) |
| Dementia | 18 (0.6%) |
Long-term health conditions self-reported in the 2021 Census. Persons may report more than one condition.
Motor Vehicles per Dwelling
| No vehicle | 101 (8.2%) |
| 1 vehicle | 492 (39.9%) |
| 2 vehicles | 467 (37.9%) |
| 3+ vehicles | 173 (14.0%) |
Schools in St Marys
ACARA 2025 school profiles for schools located in St Marys. ICSEA is shown where ACARA publishes it.
Suburbs Near St Marys
Same Postcode (5042)
More St Marys Data
Page last reviewed . Data sources: Australian Bureau of Statistics 2021 Census (CC BY 4.0), SEIFA 2021 IRSAD, ACARA school profiles 2025. How this data is sourced.