The picture is mixed. Le Mesnil-Saint-Denis ranks #26 of 91 in Yvelines, with a B+ overall. On that grade it does better than three quarters of compared French towns. It does especially well on jobs & income — 0.4 jobs per working resident; 6.9% unemployment. Buying 70 m² at the median €3,636/m² takes 6.6 years of the median income per consumption unit in the Communauté de communes de la Haute Vallée de Chevreuse. Pupils here do less well than most (D): bac results at the expected rate; brevet results 10.7 points below the expected rate.
Figures: employment, INSEE census 2023 · brevet and bac results, Ministry of Education · prices, DVF · income per consumption unit (an income adjusted for household size), INSEE Filosofi.
Hazard risk isn’t graded in France yet: national flood maps cover only some areas. The overall grade uses the other six subjects.
Each subject compares Le Mesnil-Saint-Denis with other French towns of 2,500 or more, ordered by how far its rank is from the middle. American and UK towns are graded separately.
Domaine des Ambésis, sis au hameau du Grand-Ambésis: Photo: Lionel Allorge · CC BY-SA 3.0 · Château du Mesnil: Photo: Lionel Allorge · CC BY-SA 3.0
The data
Data highlights are ordered by what stands out in Le Mesnil-Saint-Denis.
Work & commuteJobs & income A
Incomes in Le Mesnil-Saint-Denis run higher than in Yvelines’ towns and across compared French towns: a median €36,770 a year per consumption unit
22%walk, cycle or take transit
Unemployment stood at 6.9%, lower than both Yvelines’ towns (8.7%) and compared French towns (10.1%). The census found 21.5% of commuters going to work on foot, by bike or by public transport. At the census, 3.4% of working residents in Le Mesnil-Saint-Denis didn’t travel to work at all.
How working residents got to work · census 2023
Driving74%
Public transport17%
Bicycle3%
On foot2%
Motorbike or scooter1%
1,350
jobs based in Le Mesnil-Saint-Denis, 0.4 per working resident
6.9%
unemployment rate, ages 15 to 64 in the labor force · median of compared French towns 10.1%
€36,770
median annual income per consumption unit, 2023 · median of compared French towns €25,970
3%
worked without traveling (at or from home)
A
Walkability: better than 91% of compared French towns
Source: INSEE, census 2023 (commuting, employment, jobs at place of work); INSEE, Filosofi 2023 · Licence Ouverte
Schools
Brevet results near Le Mesnil-Saint-Denis run low: 76.2% passed, below Yvelines’ towns and compared French towns
92%passed the bac (general and technological)DSchool Grade
Primary schools aren’t graded: France doesn’t publish their results by school.
At the lycées within 5 km of Le Mesnil-Saint-Denis, 91.5% passed the bac, lower than both Yvelines’ towns (93.9%) and compared French towns (92.9%). The bac pro: 88% of 141 candidates passed at the 2 vocational lycées within 5 km. Ranked by results, schools here are #69 of 94 in Yvelines.
Ministry of Education (DEPP) · brevet and bac 2025, value added (IVAC, IVAL) · Licence Ouverte
Safety
For crime per resident, Le Mesnil-Saint-Denis sits below 82% of compared French towns
5.5recorded violent incidents per 1,000 residents a yearA−Safety Grade
Per 1,000 residents a year, there were 5.5 cases of violence against people and 9.6 graded property crimes (2023–2025 average). In 2025, 102 offenses were recorded in Le Mesnil-Saint-Denis. Among the graded crimes locally, the most frequent was burglary (2025).
Recorded by type · 2025
Burglary30
Criminal damage20
Family violence17
Sexual violence14
Other physical violence11
Vehicle theft10
Armed robbery0
Fraud42
Theft without violence21
Drug use18
Not in the gradeTheft without violence, drug use and fraud are shown for information but left out of the Safety Grade, which counts violence plus burglaries, vehicle thefts, thefts from vehicles and criminal damage per resident.
5.5
recorded violent incidents per 1,000 residents a year, 2023–2025 average
9.6
recorded burglaries, vehicle thefts, thefts from vehicles and acts of criminal damage per 1,000 residents a year, 2023–2025 average
102
offenses recorded in the graded categories in 2025
2.2%
of the index rests on the département’s average, used where small counts aren’t published
Source: SSMSI (Interior Ministry), recorded crime by commune, 2023–2025 · Licence Ouverte · For theft from vehicles, the count isn’t published when it’s small (five or fewer in a year of the last three), so the index uses the département’s average, 2.2% of the index here. The count covers the offense categories the Safety Grade uses.
HealthHealth B+
Le Mesnil-Saint-Denis records 80 deaths for every 100 its ages predict, against 76 in Yvelines’ towns and 88 in compared French towns
−20%deaths against expected, after care homesB+Health Grade
Care access and life expectancy are shown for context, not graded.
5 GPs practise in Le Mesnil-Saint-Denis. Average lifespans in Yvelines: 86.8 years for women, 82.3 for men (2025), against 85.9 and 80.3 nationally. From 2016 to 2025, 613 residents of Le Mesnil-Saint-Denis died, against 694 expected from France’s death rates at each age: 12% fewer.
Deaths per 100 expected · 2016–2025
Raw88
Adjusted80
Median town88
Expected100
5
GPs in Le Mesnil-Saint-Denis · 2.9 GP consultations a year per resident within reach (APL)
2.9 mi
to the nearest emergency department, Hopital Prive de L Ouest Parisien
2.9 mi
to the nearest maternity unit, Hopital Prive de L Ouest Parisien
86.8 · 82.3
years of life expectancy at birth, women · men, Yvelines, 2025 (provisional) · France 85.9 · 80.3
The median sale price of homes in Le Mesnil-Saint-Denis is €3,636/m²
€3,636/m²median sale price
Rents are the ministry’s estimates of advertised rents, not rents actually paid.
Advertised rents are estimated at €18.56/m² a month, close to Yvelines’ towns (€18.40/m²) and above compared French towns (€12.41/m²). Renting a house costs an estimated €15.93/m² a month. The market in Le Mesnil-Saint-Denis: 215 sales of houses and apartments between July 2023 and June 2026.
Median sale price per m² · Jul 2023 to Jun 2026
Le Mesnil-Saint-Denis€3,636/m²
Median of towns€2,430/m²
Yvelines median€3,717/m²
By type
Median per m²
Sales
Houses
€3,621/m²
155
Apartments
€3,669/m²
60
€18.56/m²
estimated advertised apartment rent a month, charges included (€15.85 to €21.72/m² a month)
6.6
times the median annual income per consumption unit in the intercommunality, for 70 m² at the median price
€15.93/m²
estimated advertised house rent a month, charges included
€38,610
median annual income per consumption unit, Communauté de communes de la Haute Vallée de Chevreuse
Source: DGFiP, DVF property sales (Etalab geolocated); Housing Ministry, Carte des loyers 2025; INSEE, Filosofi 2023 · Licence Ouverte
History
Le Mesnil-Saint-Denis: 2 historic monuments, none of them classé
2historic monuments
France has no History Grade yet: this card describes, it doesn’t grade.
The earliest of these monuments dates from the 16th century. Homes from before 1919 make up 3.1% of the total, lower than both Yvelines’ towns (5.2%) and compared French towns (7.4%).
Ministère de la Culture, Mérimée (Licence Ouverte 2.0) · INSEE, census 2023, homes by build period
Who lives here
Le Mesnil-Saint-Denis is a graduates’ town: 59% hold a degree, more than in Yvelines’ towns and across compared French towns
43.2median age
20% of residents have reached 65. Children under 15 make up 19%, close to Yvelines’ towns (20%) and above compared French towns (17%). Typical age in Le Mesnil-Saint-Denis: 43.2, the median.
Le Mesnil-Saint-DenisYvelines medianFrance median
Ages · share of residents
11%
Under 1515–2425–4445–6465+
Highest diploma · residents 15 and older who have left education
No diploma9%
CAP or BEP14%
Baccalauréat15%
Higher education59%
Women and men · all residents
52% women, 48% men
WomenFrance medianMen
About 93 men for every 100 women. Median share of women: Yvelines 51.6%, France 51.8%.
Alain Fontanel: Photo Claude TRUONG-NGOC, CC BY-SA 3.0
About Le Mesnil-Saint-Denis
Commune in Yvelines, Île-de-France
Le Mesnil-Saint-Denis is a commune of 7,276 people in the Communauté de communes de la Haute Vallée de Chevreuse. TownRatings compares communes, France’s local unit: each has its own mayor and its own statistics. Its area takes in the town and the countryside around it.
Built from INSEE’s 2026 official geography (COG) and IGN Admin Express boundaries
Population
7,276 (INSEE, census 2023)
Intercommunality
Communauté de communes de la Haute Vallée de Chevreuse
Département
Yvelines (78)
Région
Île-de-France
Area
3.5 sq mi (9.1 km²)
INSEE code
78397
Le Mesnil-Saint-Denis’ neighbors
The nearest towns of 2,500 or more. The map uses IGN’s commune boundaries. See them on the map →
People: INSEE, census 2023. Miles: center to center.
Questions about Le Mesnil-Saint-Denis
Is Le Mesnil-Saint-Denis safe?
It grades A− for safety, #10 of 91 in Yvelines. In 2025 police and gendarmerie recorded 30 burglaries and 20 acts of criminal damage.
Are schools in Le Mesnil-Saint-Denis good?
They grade D, better than 12% of compared French towns and #69 of 94 in Yvelines. 93% of 155 candidates passed the bac at Lycée Dumont d'Urville in 2025, a point below the expected rate given its pupils’ backgrounds. Primary schools aren’t graded: France doesn’t publish their results by school.
Is Le Mesnil-Saint-Denis expensive to live in?
By type: houses €3,621/m² (155 sales), apartments €3,669/m² (60 sales). Incomes are higher than in most compared French towns, so Le Mesnil-Saint-Denis grades C for cost of living.
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.
