Thornleigh
High household incomes and a detached-home base shape Thornleigh more than rapid growth. The suburb has 8,898 residents, a median age of 40, and household income at the 94.6th percentile nationally. Separate houses account for 76.5% of dwellings, while 4-plus-bedroom homes make up 44.4%, supporting its mortgage-belt appeal for established families. University attainment is 58.8%, or 28.7 percentage points above the national comparison, and 37.1% of residents were born overseas. For buyers comparing Thornleigh with nearby Pennant Hills, the suburb combines a family-oriented housing pattern with strong professional incomes, although its forecast annual growth of 0.41% points to measured rather than rapid expansion.
Population
8,898
Median Age
40.0
Household IncomeiMedian weekly household income (ABS Census)
$2,681/wk
DAs (12 months)iDevelopment Applications lodged in the past year
70
Thornleigh suits buyers prioritising space, established streets and access to larger homes over apartment living. Separate houses represent 76.5% of dwellings, and 44.4% have 4 or more bedrooms, compared with 39.0% for 3-bedroom homes and 8.0% for apartments. The typical monthly mortgage commitment is $2,800, while mortgage repayments equal 24.1% of household income, below the 19.8% rent-to-income figure only when comparing the different tenure groups, so buyers still need to budget carefully. A further 43.3% of households are paying a mortgage, compared with 31.7% owning outright. Thornleigh is more detached-home-oriented than the denser apartment pockets around Hornsby, but buyers should weigh renovation costs, commuting needs and exact school catchments before committing.
For Buyers
Thornleigh suits buyers prioritising space, established streets and access to larger homes over apartment living. Separate houses represent 76.5% of dwellings, and 44.4% have 4 or more bedrooms, compared with 39.0% for 3-bedroom homes and 8.0% for apartments. The typical monthly mortgage commitment is $2,800, while mortgage repayments equal 24.1% of household income, below the 19.8% rent-to-income figure only when comparing the different tenure groups, so buyers still need to budget carefully. A further 43.3% of households are paying a mortgage, compared with 31.7% owning outright. Thornleigh is more detached-home-oriented than the denser apartment pockets around Hornsby, but buyers should weigh renovation costs, commuting needs and exact school catchments before committing.
For Investors
Investor conditions are supported by a 23.4% rental share, weekly rent of $530 and a 4.1% vacancy rate. Renting is below the 43.3% share of households with a mortgage, indicating that owner-occupiers remain more prominent than tenants and that demand is not based solely on a large renter pool. Development activity is notable, with 74 applications recorded over 12 months, which may improve housing choice but can also create competing supply for some properties. The annual growth trend is 0.41%, below the pace associated with a high-growth market, while overseas migration is the primary demand driver. Thornleigh is therefore better suited to investors seeking established-area rental demand and gradual appreciation than those targeting fast price-led returns, and current yields should be calculated from the purchase price of each property.
Development Activity
Total DAs
461
Last 12 Months
70
YoY ChangeiYear-over-year change in DA lodgements
-2.8%
Avg DA CostiAverage estimated cost per DA in the past year
N/A
Monthly DA Lodgements
DA Categories
Schools in Thornleigh
Open-register school locations for education access. This is not a school-quality ranking.
Demographics
Thornleigh combines an older family structure with unusually high education and overseas-born shares compared with national benchmarks. The median age is 40, matching the national comparison, while the average household size is 2.9, or 0.4 people above the national figure. Couples with children account for 55.7% of families, compared with 29.2% for couples without children, helping explain the strong demand for 3 and 4-plus-bedroom housing. University attainment reaches 58.8%, 28.7 percentage points above national levels, and 37.1% of residents were born overseas, 15.5 points higher nationally. English, Chinese and Irish are the largest reported ancestries at 2,628, 1,307 and 776 people. Mandarin, Cantonese and Korean are prominent additional languages, supporting local links across the wider Hornsby area.
Age Distribution
Bedrooms
Dwelling Structure
76.5%
Houses
15.5%
Townhouse
8.0%
Apartment
Tenure
Thornleigh's housing is predominantly detached and owner-occupied, with 76.5% separate houses, 15.5% semi-detached dwellings and 8.0% apartments. The tenure split is 31.7% owned outright, 43.3% mortgaged and 23.4% rented, so mortgage holders form the largest group and help sustain family-oriented demand. Four-plus-bedroom dwellings account for 44.4%, slightly above the 39.0% share of 3-bedroom homes and far higher than the 12.1% share of 2-bedroom dwellings. Mortgage repayments equal 24.1% of household income, while rent equals 19.8%, giving both groups a measurable but not extreme housing burden. Compared with the denser apartment pockets around Hornsby, Thornleigh is the more detached-home-oriented choice, although its $530 weekly rent and 4.1% vacancy rate still matter for affordability and leasing decisions.
Mortgage / mo
$2,800
Rent / wkiMedian weekly rent for new bonds (April to June 2026), NSW Rental Bond Board (DCJ). Census 2021 median: $530.
$730
Bond data Jun 2026 · houses $963 · units $650
HH Size
2.9
Personal Income / wk
$1,025
Vacancy Ratei% of dwellings unoccupied on Census night (ABS 2021)
4.1%
Unoccupied
126
Rent / IncomeiMedian rent as % of household income. Over 30% = housing stress
19.8%
Mortgage / IncomeiMedian mortgage as % of household income. Over 30% = housing stress
24.1%
Community Profile
Languages Spoken at Home
Ancestry
Household Composition
55.7%
Couples with children
29.2%
Couples, no children
14.1%
Single parent
2,508
Total families
Economy & Employment
Thornleigh has a highly skilled employment base, with household income at the 94.6th percentile and an IRSAD decile of 10, placing disadvantage well below the national comparison. Healthcare is the largest industry at 17.0%, or 607 workers, followed by Professional and Technical services at 15.7% and 558 workers, Education at 14.2% and 506 workers, Finance at 7.9% and 281 workers, and Construction at 6.6% and 237 workers. Professionals number 1,722, more than twice the 789 Managers, while Clerical and Administrative roles account for 582 workers. Labour-force participation is 67.0%, unemployment is 4.2% and full-time employment is 61.4%. The 57.0% work-from-home share is higher than the 35.1% car-driver share, reflecting a professional economy that is less dependent on daily commuting than many outer suburbs.
Unemployment
4.2%
Labour Force
4,712
Unemployed
196
Source: ABS Census 2021
Socio-Economic Indexes (SEIFA)iABS index ranking suburbs from 1 (most disadvantaged) to 10 (most advantaged)
Full-time
61.4%
Part-time
29.8%
Participation
67.0%
Employed
4,516
Full-time and part-time are shares of the employed. Source: ABS Census 2021
Occupations
Top Industries
University
58.8%
Postgraduate
19.7%
Born Overseas
37.1%
Dwellings
2,973
Transport to Work
Thornleigh offers practical family amenity within a compact 3.87 square kilometre suburb housing 8,898 people at a density of 2,299.2 people per square kilometre. Work-from-home participation is high at 57.0%, compared with 35.1% travelling as car drivers, while public transport accounts for 3.9% and walking or cycling for 1.9%, so many households may still value a car for routine trips. School access includes 2 nearby government primary schools, but families should confirm the exact intake area and enrolment rules because catchments can differ by address. The IRSAD decile is 10, well above the national midpoint, reflecting strong socioeconomic conditions. For safety decisions, check recent NSW Police incident information and inspect the exact street at different times, since local conditions can vary across a suburb of 3.87 square kilometres.
Drive
35.1%
Public Transport
3.9%
Walk / Cycle
1.9%
Work from Home
57.0%
Population Forecast
+0.41%/yr
(+82 people/yr)
EstablishedThornleigh is an established, slow-growth market, with the forecast annual trend at 0.41% and wider-area population change at 6.2% over 10 years. Overseas migration is the primary growth driver, which fits the suburb's 37.1% overseas-born share and 15.5 percentage-point advantage over the national comparison. The shift trajectory is Mixed: rent growth has reached 34.1%, the senior share has increased by 2.3 percentage points, and the young share has declined by 1.5 points. Gentrification is classified as Not gentrifying with a score of 10, although another shift measure records Early signs at 33, suggesting selective change rather than a broad transformation. Growth is likely to remain measured because Thornleigh is already developed and financially established, while overseas migration provides ongoing demand.
Historical + Forecast
Hamilton-Perry + Holt smoothing on ERP 2001-2025
Age Cohort Forecast
Primary Driver
Overseas Migration
Net Overseas / yr
+239
Net Internal / yr
-86
Gentrification Signal
Not gentrifying
Strong overseas inflow +239/yr
National Ranking iPercentile rank among ~15,000 AU suburbs. 90% = higher than 90% of suburbs
How Thornleigh compares to ~15,000 Australian suburbs
Frequently Asked Questions
Is Thornleigh a good suburb to live in?
Thornleigh suits households seeking larger homes, established services and strong socioeconomic conditions. It has 8,898 residents, a median age of 40, 76.5% separate houses and an IRSAD decile of 10. The 57.0% work-from-home share also supports local routines, although the 3.9% public transport share means many residents may still depend on cars.
What is the median house price in Thornleigh?
A current median house price should be checked against a live market source before making an offer. Thornleigh has 76.5% separate houses and 44.4% four-plus-bedroom dwellings, while household income sits at the 94.6th percentile nationally. Those figures provide useful context for comparing individual listings, but they do not replace a current sale-price measure.
What schools are in Thornleigh?
Thornleigh has 2 nearby government primary schools: Thornleigh West Public School and Normanhurst West Public School. Confirm the exact intake area and current enrolment position before buying, because catchments can differ by address. Families should also compare secondary options across the wider Hornsby area rather than relying only on the suburb boundary.
Is Thornleigh safe?
For a current safety view, check NSW Police incident information for the exact street and most recent 12-month period. Thornleigh has 8,898 residents and a density of 2,299.2 people per square kilometre, so conditions can vary by pocket. Inspect lighting, traffic, parking and evening activity in person before choosing a home.
Is Thornleigh good for property investment?
Thornleigh can suit investors seeking established rental demand rather than rapid growth. Weekly rent is $530, vacancy is 4.1% and 23.4% of households rent. However, the annual growth trend is 0.41% and 74 development applications were recorded over 12 months, so investors should assess competing supply, property condition and achievable yield carefully.
How is Thornleigh's population changing?
Growth is measured rather than rapid. The wider area's 10-year population change is 6.2%, with an annual trend of 0.41% and overseas migration as the primary driver. The shift trajectory is Mixed, with the senior share up 2.3 percentage points and the young share down 1.5 points, indicating gradual ageing alongside continued international demand.
What development is happening in Thornleigh?
There were 74 development applications over 12 months, including dwelling house applications and a neighbourhood shop proposal. This level of activity indicates ongoing renewal rather than a single major project. Buyers should check the exact street for construction timing, traffic effects and nearby approvals, especially when comparing established homes with newer stock.
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 education open registers (school locations), 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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