Castlecrag, NSW
By Lauren McCaleb · Reviewed by Dylan Duncan ·
Castlecrag is a leafy harbourside suburb on Sydney's lower North Shore, about eight kilometres north of the city centre in the City of Willoughby, almost encircled by the waters of Middle Harbour. It was planned in the 1920s by the architects Walter Burley Griffin and Marion Mahony Griffin, the couple who had laid out Canberra, and named after a rocky outcrop above the harbour known locally as Edinburgh Castle. The Griffins conceived it as a model community living in harmony with the bush: houses of local stone with flat roofs and no front fences, roads that follow the land's natural contours, and a generous share of the land kept as leafy reserves. Many of its streets are named for parts of a castle, among them The Bastion, The Rampart and The Parapet, while the main thoroughfare is Edinburgh Road.
Among Australia's more advantaged suburbs
Castlecrag is more socio-economically advantaged than about 99% of the 14,462 Australian suburbs we score, based on the ABS SEIFA index (raw score 1195, where about 1000 is the national average).
A socio-economic measure from ABS Census data — not a measure of how good a suburb is to live in or visit. How we calculate this.
Castlecrag at a glance
- Population (2021)
- 2,965
- Median age
- 47
- Median weekly household income
- $4,675
- SEIFA score
- 1195
- Coordinates
- -33.8003, 151.2206
Castlecrag demographics (2021 Census)
The figures below profile Castlecrag using the Australian Bureau of Statistics 2021 Census; every percentage is a share of a clearly stated Census count, so each one traces back to the source. At a glance, the largest age group is mid-life (45–64) at 34%, 11% of homes are rented, and 33% of residents were born overseas.
Age profile
| Age group | People | Share |
|---|---|---|
| Children (0–14) | 541 | 18% |
| Youth (15–24) | 470 | 16% |
| Young adults (25–44) | 389 | 13% |
| Mid-life (45–64) | 1,012 | 34% |
| Seniors (65+) | 557 | 19% |
Share of the 2,969 people counted by age.
Housing and households
| Tenure | Dwellings | Share |
|---|---|---|
| Owned outright | 464 | 49% |
| Owned with a mortgage | 368 | 39% |
| Rented | 104 | 11% |
| Dwelling type | Dwellings | Share |
|---|---|---|
| Houses | 930 | 97% |
| Townhouses & semis | 17 | 2% |
| Flats & apartments | 11 | 1% |
Tenure and dwelling shares are of the roughly 962 occupied private dwellings in Castlecrag.
- Median weekly rent
- $1,010
- Median monthly mortgage
- $4,333
- Average household size
- 3 people
- Median weekly family income
- $4,857
- Median weekly personal income
- $1,446
Community and culture
- Born overseas
- 947 (33%)
- Speaks a language other than English at home
- 560 (19%)
- Aboriginal and/or Torres Strait Islander
- 3 (0%)
Work and education
- Completed Year 12
- 1,964 (88%)
- Labour-force participation
- 62.6%
- Unemployment rate
- 4.4%
- Employed full-time
- 842
- Employed part-time
- 496
Source: ABS Census of Population and Housing, 2021 (General Community Profile, by Suburb and Locality). © Australian Bureau of Statistics, released under CC BY 4.0. How we group bands and derive each share is set out on our methodology page.
Weather and climate in Castlecrag
Based on 2014–2023 records, the warmest month in Castlecrag is January (average daytime high around 25.7°C) and the coolest is July (around 16.5°C). The area receives roughly 1084 mm of rain across the year.
| Month | Avg high | Avg low | Rain |
|---|---|---|---|
| Jan | 25.7°C | 19.3°C | 104 mm |
| Feb | 25.1°C | 19°C | 119 mm |
| Mar | 24°C | 18°C | 186 mm |
| Apr | 21.9°C | 15°C | 100 mm |
| May | 19.2°C | 11.7°C | 56 mm |
| Jun | 16.5°C | 9.8°C | 74 mm |
| Jul | 16.5°C | 8.7°C | 70 mm |
| Aug | 17.3°C | 9.2°C | 67 mm |
| Sep | 19.6°C | 11.3°C | 55 mm |
| Oct | 21.8°C | 13.7°C | 92 mm |
| Nov | 22.8°C | 15.5°C | 78 mm |
| Dec | 24.7°C | 17.5°C | 83 mm |
Climate normals, 2014–2023 (Open-Meteo, ERA5 reanalysis).
Common questions about Castlecrag
Where is Castlecrag?
Castlecrag is a suburb of New South Wales, Australia.
What is the population of Castlecrag?
At the 2021 Census, Castlecrag had a population of about 2,965.
Is Castlecrag an advantaged area?
Castlecrag has an ABS SEIFA score of 1195, where about 1000 is the national average — higher scores indicate greater relative socio-economic advantage. That gives it a Suburb Score of 99 out of 100 — more socio-economically advantaged than about 99% of Australian suburbs.
What is the weather like in Castlecrag?
Castlecrag has average daytime highs of about 21.3°C and overnight lows of about 14.1°C, with roughly 1,084 mm of rain across the year (based on 2014–2023 climate normals).
Does Castlecrag have high household incomes?
Castlecrag has one of the highest median weekly household incomes in Australia — the 5th-highest among suburbs with at least 1,000 residents at the 2021 Census ($4,675 per week).
Where Castlecrag ranks
Castlecrag appears in these data-driven guides — each a transparent sort on a single ABS figure shown on this page.
Nearby suburbs in New South Wales
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