Castlecrag
With household income sitting at the 99.8th percentile nationally, Castlecrag stands among the most financially concentrated suburbs in Australia. A median house price of $4,300,000, a population of just 2,965 across 1.51 square kilometres, and 87.2% of residents choosing to stay between census periods together signal a suburb that retains wealth rather than cycling it. University qualifications reach 71.0%, which is 40.9 percentage points above the national figure. The median age of 47 is 7 years older than the national median, consistent with the 49.6% who own their homes outright and the 63.6% of dwellings with four or more bedrooms.
Population
2,965
Median Age
47.0
Household IncomeiMedian weekly household income (ABS Census)
$4,675/wk
DAs (12 months)iDevelopment Applications lodged in the past year
39
Median House
$4.3M
2024-2025 (PSI derived)
The median house price of $4,300,000 places Castlecrag well above the Sydney median and most other Lower North Shore comparisons. Price data shows a move from $4,190,000 in 2024 to $4,335,000 in 2025, a 3.5% one-year gain. Stock is overwhelmingly separate houses at 96.7%, with apartments accounting for only 1.1%, so buyers are competing for a genuinely scarce dwelling type. Bedroom configuration is large-home dominant, with 63.6% of dwellings having four or more bedrooms and 28.3% at three bedrooms. Monthly mortgage repayments average $4,333, yet the mortgage-to-income ratio sits at just 21.4%, below the 30% stress threshold, because household incomes are in the 99.8th percentile nationally.
For Buyers
The median house price of $4,300,000 places Castlecrag well above the Sydney median and most other Lower North Shore comparisons. Price data shows a move from $4,190,000 in 2024 to $4,335,000 in 2025, a 3.5% one-year gain. Stock is overwhelmingly separate houses at 96.7%, with apartments accounting for only 1.1%, so buyers are competing for a genuinely scarce dwelling type. Bedroom configuration is large-home dominant, with 63.6% of dwellings having four or more bedrooms and 28.3% at three bedrooms. Monthly mortgage repayments average $4,333, yet the mortgage-to-income ratio sits at just 21.4%, below the 30% stress threshold, because household incomes are in the 99.8th percentile nationally.
For Investors
The rental market in Castlecrag is thin by design. Renters make up just 11.1% of households, the lowest tenure slice, against 49.6% who own outright. Weekly rent of $1,010 against a $4,300,000 median implies a gross yield below 1.3%, among the lowest in any Sydney suburb. The vacancy rate of 6.4% is elevated relative to the broader Sydney average, reflecting limited turnover rather than oversupply. Development activity ran to 37 applications in the past 12 months, mostly alterations and additions to existing houses rather than new dwellings, consistent with a low-supply, established-ownership market. Stability rather than yield is the investment proposition here.
Development Activity
Total DAs
198
Last 12 Months
39
YoY ChangeiYear-over-year change in DA lodgements
+2.6%
Avg DA CostiAverage estimated cost per DA in the past year
N/A
Monthly DA Lodgements
DA Categories
Demographics
The median age of 47 is 7 years above the national figure. Average household size of 3.0 is 0.5 above national, reflecting the 42.9% of families who are couples with children. University qualifications at 71.0% run 40.9 percentage points above national, among the highest found in any Australian suburb. Overseas-born residents account for 32.6%, which is 11.0 points above national. Leading ancestry groups are English (1,081), Irish (406) and Chinese (377). Non-English languages are modest: Mandarin (56 speakers) and Cantonese (52) top the list. Volunteering reaches 25.9%, well above typical suburban rates.
Age Distribution
Bedrooms
Dwelling Structure
96.7%
Houses
1.8%
Townhouse
1.1%
Apartment
Tenure
Tenure splits sharply toward ownership: 49.6% own outright, 39.3% carry a mortgage, and only 11.1% rent, the reverse of most Sydney suburbs where renters outnumber outright owners. The stock is almost entirely separate houses at 96.7%, with apartments at just 1.1%, so the detached-house market defines all price outcomes. Four-plus bedroom homes account for 63.6% of dwellings, making large family housing the dominant product. The median price moved from $4,190,000 in 2024 to $4,335,000 in 2025, a 3.5% gain. Monthly mortgage repayments average $4,333, but the mortgage-to-income ratio of 21.4% stays below the 30% stress threshold because household incomes rank in the 99.8th percentile nationally.
Median House Price Trend
Source: State Valuer-General
Mortgage / mo
$4,333
Rent / wk
$1,010
HH Size
3.0
Personal Income / wk
$1,446
Vacancy Ratei% of dwellings unoccupied on Census night (ABS 2021)
6.4%
Unoccupied
66
Rent / IncomeiMedian rent as % of household income. Over 30% = housing stress
21.6%
Mortgage / IncomeiMedian mortgage as % of household income. Over 30% = housing stress
21.4%
Community Profile
Languages Spoken at Home
Ancestry
Household Composition
21.1%
Couples, no children
2,662
Total families
Economy & Employment
The workforce clusters in high-paying knowledge industries: Professional and Technical services leads at 25.8% (303 workers), Finance at 16.8% (197) and Healthcare at 14.6% (172). By occupation, Professionals number 625 and Managers 392, consistent with 71.0% university qualifications, which is 40.9 points above national. Full-time employment runs at 62.9% and the unemployment rate at 4.6%. Personal weekly income averages $1,446 and family weekly income $4,857. Some 854 residents are not in the labour force, reflecting the median age of 47 and the large cohort of outright owners who have moved beyond active employment.
Socio-Economic Indexes (SEIFA)iABS index ranking suburbs from 1 (most disadvantaged) to 10 (most advantaged)
Full-time
62.9%
Part-time
32.5%
Participation
57.6%
Employed
1,338
Occupations
Top Industries
University
71.0%
Postgraduate
22.8%
Born Overseas
32.6%
Dwellings
962
Transport to Work
Private car use is dominant at 84.9% of commuters, with public transport at just 4.6%. The peninsula geography limits rail access, making car-dependency structural rather than a preference. Volunteering reaches 25.9%, above most suburban rates, driven by the stable long-term resident base where 87.2% stayed between census periods. Only 2.7% of residents (79 people) need daily assistance, consistent with a well-resourced community. No schools are recorded within the boundary, so families depend on institutions in neighbouring suburbs such as Northbridge and Willoughby, a practical trade-off for a suburb where household income ranks in the 99.8th percentile nationally.
Drive
84.9%
Public Transport
4.6%
Walk / Cycle
5.5%
Work from Home
N/A
National Ranking iPercentile rank among ~15,000 AU suburbs. 90% = higher than 90% of suburbs
How Castlecrag compares to ~15,000 Australian suburbs
Frequently Asked Questions
Is Castlecrag a good suburb to live in?
Castlecrag consistently attracts and retains high-income households, with family weekly income of $4,857 and household income in the 99.8th percentile nationally. University qualifications reach 71.0%, which is 40.9 points above national. The 87.2% residential retention rate signals that residents who move in tend to stay, though the $4,300,000 median house price means entry is limited to a narrow buyer pool.
What is the median house price in Castlecrag?
The median house price is $4,300,000 based on 2024-2025 data, up from $4,190,000 in 2024 to $4,335,000 in 2025, a 3.5% one-year gain. Monthly mortgage repayments average $4,333. Despite the very high price, the mortgage-to-income ratio sits at 21.4%, below the 30% stress threshold, because household incomes rank in the 99.8th percentile nationally.
What schools are in Castlecrag?
No schools are recorded inside the Castlecrag boundary in this dataset. Families rely on schools in neighbouring suburbs including Northbridge, Willoughby and Cammeray. Despite the absence of local schools, educational attainment is very high: 71.0% of residents hold university qualifications, which is 40.9 percentage points above the national figure.
Is Castlecrag safe?
Detailed crime statistics are not available for Castlecrag in this dataset. As indirect indicators, only 2.7% of residents (79 people) require daily assistance, the unemployment rate is 4.6%, and 87.2% of residents stayed put between census periods, consistent with a stable, low-disadvantage community. Household income sits in the 99.8th percentile nationally.
Is Castlecrag good for property investment?
The investment profile here favours capital preservation over yield. Weekly rent of $1,010 against a $4,300,000 median implies a gross yield below 1.3%, well below typical Sydney averages. The vacancy rate of 6.4% is elevated for such a tightly held suburb. However, the 3.5% price gain from 2024 to 2025 and the 87.2% retention rate among residents suggest strong demand fundamentals for long-term holders.
How is Castlecrag's population changing?
The population of 2,965 is stable, with an 87.2% residential retention rate between census periods and a turnover rate of only 12.8%. The median age of 47 is 7 years above the national figure, and the aging resident profile means natural population growth is limited. Development activity of 37 applications in 12 months is dominated by alterations to existing homes rather than new dwellings, so the housing stock is not expanding materially.
What languages are spoken in Castlecrag?
About 32.6% of residents were born overseas, which is 11.0 percentage points above the national figure. English is the dominant language. The most common non-English languages are Mandarin (56 speakers) and Cantonese (52), with French (18), German (14) and Greek (11) also represented. The overseas-born population is diverse, reflecting the suburb's appeal to internationally mobile professional households.
How much development is happening in Castlecrag?
There were 37 development applications lodged in the past 12 months. The samples show almost all are alterations and additions to existing dwelling houses rather than new builds, which is typical for an established, built-out suburb on a 1.51 square kilometre peninsula. The low renter share of 11.1% and the 96.7% separate-house stock profile mean new multi-dwelling supply is structurally constrained.
How to read these comparisons
Phrases like "above the national average" reference the unweighted median across Australian suburbs with more than 1,000 residents, not population-weighted national figures. Suburb-level medians are more useful for ranking suburbs against each other; ABS census headlines are population-weighted (so dominated by Sydney and Melbourne) and can read very differently.
Current baseline (refreshed 2026-05-10): median age 40, university-educated 30.1%, born overseas 21.6%, average household size 2.5 people.
Data sources: ABS 2021 Census (demographics, income, tenure), state Valuer-General (house prices), Department of Jobs SALM (unemployment), ACARA (school ICSEA), state Crime Statistics agencies (offences), council DA portals (development applications). Population forecasts use a Hamilton-Perry cohort model calibrated to ABS ERP.
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