45% of households are couples with children, more than in 99% of compared French towns
By its share of empty homes (3.7%), Lagny-le-Sec is below 90% of compared French towns. 3.4% of households have no car. Compared with other places, residents aged 65 and over are scarce here: 16%, fewer than in 88% of compared French towns. At the 2023 Census, 2,043 people lived locally, in 760 households.
Throughout this page, the Oise median and the France median are the median of compared communes (those with an overall grade), each figure its own median. Source: INSEE, census 2023.
What stands out about the people of Lagny-le-Sec
A town of families
45% of households are couples with children and 5.3% single parents with children; 20% of residents are under 15. Households ↓
Written from INSEE’s census 2023 on this page, against compared French towns.
+1% since 2012: slower than 66% of compared French towns
Residents at INSEE’s last three censuses, each recast in the 2026 commune boundaries. France has no yearly estimate by commune between censuses.
2012 to 2023
2017 to 2023
From 2012 to 2017 the population moved +2%, and from 2017 to 2023 −1%; the median compared French town changed +5% and the median Oise town +2%.
Lagny-le-Sec: 13% of residents are 15 to 24, above 85% of compared French towns
Shares of residents by age at the 2023 census.
Age groups · share of residents
Median age of the 3,798 compared French towns
■ Lagny-le-Sec 42.5. The median compared French town: 44.
With a median age of 42.5, Lagny-le-Sec is younger than 62% of compared French towns. As a yardstick, 11% of residents are 15 to 24 in the typical compared French town.
Women and men · all residents
50% women, 50% men
About an even split. Median share of women: Oise 51.7%, France 51.8%.
A smaller share of one-person households than 99% of compared French towns: 21%
A household is everyone who shares a main home (résidence principale). Household types come from INSEE’s fuller sample of a quarter of census forms.
Against the Oise median and the France median
Living alone · share
The figure for single-parent households is 5.3% in Lagny-le-Sec and 10% in the typical compared French town. In the typical compared French town, one-person households come to 35%. There are 2.7 people in the average household.
A lower share of flats than 92% of compared French towns, at 6.9%
Every home the census counted: main residences, second homes and occasional dwellings (INSEE counts them together), and empty homes. Owning and renting are on Cost of living.
All homes · share of homes
Type of home
Cars per household · share of households
Long tenure is the mark of 24% of households (30 years or more), short tenure of 4.5% (under two years). Households in social housing are rarer here than in 99% of compared French towns. Add to that, the share of second homes trails 80% of compared French towns: 1%.
The middle resident’s standard of living: €31,690 a year
The standard of living (niveau de vie) is a household’s disposable income after taxes and benefits, divided by its consumption units (UC) to allow for its size and make-up: 1 for the first adult, 0.5 for each other person 14 or older, 0.3 for each child under 14.
Medians of compared communes. Source: INSEE, Filosofi 2023.
At €31,690 a year per consumption unit, the median standard of living here is higher than in 90% of compared French towns. The share living below the poverty line is 3.0%.
Households headed by a manager or professional: 12%, a higher share than 63% of compared French towns
Households by the socio-professional group (PCS) of their reference person, INSEE’s own categories. Jobs and commuting are on the Work & commute page.
Households by reference person’s group · share of households
By its share of households headed by a manual worker (13%), Lagny-le-Sec is below 60% of compared French towns. Typically, 9.4% of households are headed by a manager or professional in the typical compared French town. A third of households are headed by a retired person.
Each household is counted once, by the occupation of its reference person (usually the oldest working adult).
A larger share of immigrants than 60% of compared French towns: 8%
INSEE publishes two measures, which overlap but aren’t the same. Neither is the UK’s “born abroad”.
Share of residents · census 2023
Immigrant (immigré)
Born abroad, not French at birth. Someone stays an immigrant after becoming French. A French citizen born abroad (for example in Algeria before 1962) is not one.
Foreign national (étranger)
Not a French citizen today, wherever born. A child born in France to foreign parents can be a foreign national without being an immigrant.
Here, 4.2% of residents are foreign nationals. Set beside that, 6.5% of residents are immigrants in the typical compared French town.
INSEE publishes no country of birth or ethnicity by commune in these tables, and the census doesn’t ask about religion.
A larger share of married residents than 96% of compared French towns: 52%
Residents 15 and over by how they live: the census asks both the legal status and whether people live as a couple.
Residents 15 and over · share
Nearly a quarter of residents 15 and over are single; in the typical compared French town the figure is 25%. The benchmark for married residents in the typical compared French town: 43%.
Lagny-le-Sec ranks below 78% of compared French towns on adults with no qualification: 14%
Highest diploma of residents 15 and over who have left education, in French terms: the levels don’t map one-to-one to UK or U.S. ones.
Highest diploma · 15 and over, out of education
The share of graduates of higher education is 36%, against 30% in the typical compared French town. The benchmark for adults with no qualification in the typical compared French town: 19%.
Ranked by age, 10th youngest of 41 French towns this size
The 40 compared French towns nearest in population, by median age. Hover for each one’s second homes and immigrants; click for its page.
At the ends of the range sit Villejust (37.2), the youngest, and Prayssac (62.3), the oldest.
No nearby town is as old as Lagny-le-Sec
The nearest towns of 2,500 or more, colored by median age. Source: INSEE, census 2023.
| Town | Median age | 65+ | Second homes | Immigrants |
|---|---|---|---|---|
| Lagny-le-Sec | 42.5 | 16% | 1% | 8% |
| Le Plessis-Belleville 4,009 · 1.1 mi | 37.2 | 14% | 0.9% | 13% |
| Saint-Pathus 6,479 · 2.3 mi | 37.4 | 12% | 0.8% | 7.5% |
| Dammartin-en-Goële 11,907 · 3.4 mi | 34.8 | 10% | 0.9% | 12% |
| Othis 6,717 · 3.5 mi | 39.5 | 14% | 0.7% | 8.6% |
| Saint-Mard 3,832 · 3.9 mi | 38.8 | 14% | 0.7% | 9.3% |
| Saint-Soupplets 3,542 · 4.3 mi | 39.3 | 17% | 1.6% | 8.5% |
Health, work, housing and schools
What this data can and can’t tell you
- Census 2023. INSEE’s census is a rolling survey: a fifth of small communes each year, 8% of homes in large ones each year. “2023” pools the surveys of 2021 to 2025, so the figures describe the town around 2023, not on one day.
- Medians of compared communes. The comparisons are the median of the département’s compared communes and of France’s (those with an overall grade), each figure its own median: not the total for the département or for France, which large cities pull towards their own figures.
- Immigrants and foreign nationals. INSEE’s two measures: an immigrant was born abroad without French nationality; a foreign national isn’t French today. Neither is a count of people born abroad, which INSEE doesn’t publish by commune.
- Second homes. Homes used for holidays or weekends, with occasional dwellings (kept for work, for example), which INSEE counts together. Their owners are counted where they live, not here.
- Standard of living. INSEE’s Filosofi: disposable income per consumption unit, from tax and benefit files, 2023. The poverty rate is the share of residents below 60% of France’s median. Not published for the smallest communes.
- What France doesn’t ask. The French census asks nothing about ethnicity, religion, language or health, so this page has no such section.
Questions about who lives in Lagny-le-Sec
What is the population of Lagny-le-Sec?
2,043 at INSEE’s 2023 census, about the same as in 2012 (2,026).
How old are Lagny-le-Sec’s residents?
The median age is 42.5, younger than 62% of compared French towns. 26% are under 18 and 16% 65 or older.
How many second homes are there in Lagny-le-Sec?
8, with occasional dwellings: 1% of all homes, against 2.1% for the median compared French town.
How many immigrants live in Lagny-le-Sec?
INSEE counts 160 immigrants (born abroad, not French at birth), 8% of residents, and 85 foreign nationals (4.2%). The medians of compared French towns are 6.5% and 4.3%.
What is the median income in Lagny-le-Sec?
€31,690 a year per consumption unit in 2023 (median of compared French towns €25,970); 3.0% of residents live below the poverty line. Source: INSEE, Filosofi.
Sources: INSEE, census 2023 (population, ages, households, homes, marital status, diplomas, immigrants, foreign nationals, employment), 2026 geography · INSEE, Filosofi 2023 (standard of living, poverty) · IGN Admin Express (boundaries) · Medians and percentiles: TownRatings, over compared French towns, updated November 4, 2026. Under the Licence Ouverte / Open Licence 2.0 (Etalab).
Contains public sector information under the Licence Ouverte / Open Licence 2.0 (Etalab): INSEE, DGFiP, the Interior Ministry’s statistics service (SSMSI), the Ministry of Education (DEPP), the Health Ministry’s statistics service (DREES) and the Housing Ministry (Carte des loyers). Commune boundaries: IGN Admin Express.