St Marys flood map & planning overlays
A planning-constraint profile of St Marys
(Penrith, NSW) - 10.62 km², mapped from live council and
state overlay data. This suburb is highly constrained.
Profile updated 3 October 2026.
Suburb-wide figures; the free map shows which overlays touch your lot.
Constraint readout
10.62 km² - this suburb is highly constrained by planning overlays.
Elevation hillshade with street names, clipped to St Marys's boundary, with the flood, bushfire and environmental overlays drawn on top. Magenta is where aircraft were observed in the sampled period, brightest below 3,000 ft.
Nearby suburbs, nearest first
Aircraft noise and flight paths over St Marys
Two different things, kept apart on purpose. The ANEF contour is the planning instrument - a forecast published per airport that planning schemes use to control noise-sensitive development. Observed overflight is what a sampled aircraft-tracking feed actually recorded over the suburb - where aircraft flew, how low and how often.
Observed overflight - sampled 4 Sep to 2 Oct 2026
typical observed square 1 a day
Night movements: observed, lowest 500 ft - night is sampled as often as day, but night traffic is light, so this is a floor and no rate can be put on it.
Traffic is sampled rather than watched continuously, so every figure is a floor: aircraft not captured between samples are not represented. Rates are per 500 m square - the busiest square in the suburb, not a count of flights over the suburb - and a square is only rated where enough traffic was seen to measure it. Altitudes are above mean sea level. Flight paths change with runway use, weather, season and airspace design. This is a record of observed traffic; it is not a noise contour and not a planning control.
St Marys at a glance
How St Marys is zoned
Buying in St Marys? The zoning, flood and bushfire lines on the section 10.7 certificate attached to the contract are mapped controls - see our s10.7 certificate guide.
Across its 10.62 km², St Marys is highly constrained by planning overlays. About 10% of the suburb sits within a mapped flood overlay, and 26% is flagged bushfire-prone. There are 36 heritage-listed sites on record, and the dominant land-use zone is General Industrial. The median lot measures about 667 m² across 3,800 parcels.
Who lives in St Marys
Census 2021 figures published by the ABS for the St Marys suburb boundary itself, not a wider region.
Socio-economic standing
ABS SEIFA 2021 ranks every Australian suburb. Decile 1 is the most disadvantaged tenth of the country, decile 10 the least.
Score 906, and decile 2 within New South Wales. The national average is 1000.
Age profile
Share of St Marys's 13,256 residents in each ABS age band.
Population trend, 2001 to 2025
Estimated resident population of St Marys - North St Marys, the wider ABS statistical area containing St Marys. There is no annual population series published at suburb level, so this describes the surrounding area rather than St Marys itself.
13,398 in 2001 to 18,757 in 2025, up 40%.
Source: ABS Census 2021 and SEIFA 2021 (Suburbs and Localities), Regional Population (SA2), CC BY 4.0. Small counts are randomly adjusted by the ABS.
St Marys data sources and coverage
“Not mapped” means we hold no source layer for this suburb - never an all-clear.
| Dataset | Coverage | Publisher |
|---|---|---|
| Flood mapping | Mapped | NSW Government spatial services, NSW ePlanning and published council flood studies |
| Bushfire-prone mapping | Mapped | NSW Government spatial services, NSW ePlanning and published council flood studies |
| Zoning | Mapped | NSW Government spatial services, NSW ePlanning and published council flood studies |
| Heritage and environment | Mapped where published | NSW Government spatial services, NSW ePlanning and published council flood studies |
| Aircraft noise contours (ANEF) | Not held | NSW Government spatial services, NSW ePlanning and published council flood studies, Defence |
| Observed flight paths | Observed | adsb.lol, under the Open Database License |
| Demographics | Available | Australian Bureau of Statistics (2021 Census and SEIFA) |
Profile last materially updated 3 October 2026. See the methodology and full source list. Source data changes over time and critical decisions should be checked with the responsible authority.
Check a specific St Marys address
See exactly which overlays touch a single property - the interactive map is free. Need it on paper? A full planning PDF is just $9.
Aircraft have been seen below 3,000 ft over about 80% of St Marys. The report's Aircraft Overflight page narrows that to the address itself: how many aircraft a day, how low, and at what heights.
Published flood models are held over parts of St Marys. The free check tells you whether one reaches an address; where it does, a Flood Model Report is +$9 with the planning report.
Building or pricing a slab? The $119 geotechnical desktop report covers geology, soils, bores and an indicative AS 2870 site class for a St Marys lot.
See what's in the $9 report →St Marys planning - frequently asked
Is St Marys flood-prone?
About 10% of St Marys falls within a mapped flood overlay, against the council-wide suburb average of 12%. Published flood models are held over parts of St Marys; the free check on the Flood Model Report page says whether one reaches a given address.
Is St Marys bushfire-prone?
Around 26% of St Marys is mapped as bushfire-prone, compared with a Penrith average of 42%.
Is St Marys under a flight path?
Aircraft were observed below 3,000 ft over about 80% of St Marys, and over about 93% at any altitude up to 10,000 ft, in the period sampled (4 Sep 2026 to 2 Oct 2026). The lowest measured aircraft was at 500 ft, with an average of 2,000 ft. At the busiest point in the suburb about 5 aircraft a day were recorded passing over one 500 m square. Traffic is sampled rather than watched continuously and flight paths change with runway use, weather and season; the ANEF contour is the planning instrument.
What is the zoning in St Marys?
The dominant planning zone in St Marys is General Industrial, though the suburb also includes Medium Density Residential and Low Density Residential.
Does St Marys have heritage-listed places?
St Marys has 36 heritage-listed places on record.
What is the typical lot size in St Marys?
Across 3,800 surveyed parcels in St Marys, the median lot size is about 667 m². There are also 4 registered easements mapped in the suburb.
Does St Marys have a train station?
Yes - St Marys has 1 train station: St Marys Station. It is also served by 173 bus stops.
What is the population of St Marys?
At the 2021 Census St Marys had 13,256 usual residents, with a median age of 34 and an average household size of 2.5 people. The wider St Marys - North St Marys statistical area, which contains St Marys, went from 13,398 people in 2001 to 18,757 in 2025, up 40%.
Is St Marys an advantaged suburb?
On the ABS SEIFA 2021 index of relative socio-economic advantage and disadvantage (IRSAD), St Marys scores 906 and sits in decile 2 of 10 nationally and decile 2 within New South Wales (decile 1 is the most disadvantaged tenth, decile 10 the least).
What is the median household income in St Marys?
Median household income in St Marys was $1,437 a week at the 2021 Census, against $2,067 for the typical suburb in Penrith. Median rent was $365 a week and the median mortgage repayment $1,847 a month.
Compare nearby suburbs
| Nearby suburb | Distance | Flood mapped | Bushfire-prone |
|---|---|---|---|
| North St Marys | 1.3 km | 0% | 38% |
| Werrington County | 2.0 km | 2% | 42% |
| Werrington | 2.0 km | <1% | 25% |
| Tregear Blacktown |
2.1 km | 13% | 21% |
| Ropes Crossing Blacktown |
2.5 km | 11% | 78% |
| Lethbridge Park Blacktown |
3.0 km | 8% | 1% |
| Whalan Blacktown |
3.1 km | 11% | 7% |
| Oxley Park | 3.2 km | 0% | 23% |
| Claremont Meadows | 3.2 km | 0% | 33% |
| Emerton Blacktown |
3.5 km | 10% | 0% |