Château de Villiers-le-Mahieu
Modernised castle in Villiers-le-Mahieu in the Yvelines département of France.
Each edition grades its towns against each other only.

5 of the 7 places to visit in and around Osmoy are châteaux or heritage sites. All of them lie outside Osmoy. Day-trippers head 30 km out to Château de Versailles.
Along with Château de Villiers-le-Mahieu, see 4 châteaux and a zoo.
Best known first: by how many Wikipedia and sister-site articles cover each place (Wikidata’s count). It isn’t a ranking of how good they are.
The farthest of them, Réserve africaine de Thoiry, is 4.9 km out.
The first 20 on the list, numbered as below. The shape is the commune of Osmoy; the orange dot is its centre. © OpenStreetMap contributors · commune boundary: IGN
Châteaux or heritage sites lead the count with 5 of 7.
Dark: in Osmoy. Light: in the communes within 5 km of its centre.
All 7 on the list lie within 5 km of its centre.
Modernised castle in Villiers-le-Mahieu in the Yvelines département of France.
Nothing is mapped in Osmoy itself; these are within 5 km of its centre.
First of the 12 big names within reach is Château de Versailles, 30 km away.
AttractionChâteau de Versailles30 km east, in Versailles
AttractionArche de la Défense38 km east, in Puteaux
GardenBois de Boulogne39 km east, in Paris 16e
AttractionPetit Trianon29 km east, in VersaillesChâteauChâteauChâteau de Saint-Germain-en-Laye28 km east, in Saint-Germain-en-LayeMuseumMuseumVilla Savoye24 km east, in Poissy
AttractionGrand Trianon29 km east, in VersaillesAttractionAttractionAbbaye de Port-Royal-des-Champs à Magny-les-Hameaux26 km southeast, in Magny-les-HameauxChâteauChâteauChâteau de Malmaison33 km east, in Rueil-Malmaison
MuseumChâteau de Rambouillet25 km south, in Rambouillet
ChâteauChâteau d'Anet20 km west, in Anet
MuseumManufacture nationale de Sèvres37 km east, in SèvresPlaces within 40 km of Osmoy with an article in both French and English Wikipedia, nearest first.
Nothing is mapped in Osmoy itself, but within 5 km there are Château de Villiers-le-Mahieu, Château de Béhoust, Château de Septeuil and Réserve africaine de Thoiry.
No museum or gallery is mapped in Osmoy or within 5 km.
The nearest with articles in both French and English Wikipedia: Château de Versailles (30 km), Arche de la Défense (38 km), Bois de Boulogne (39 km), Petit Trianon (29 km).
From OpenStreetMap and Wikidata: named museums, galleries, châteaux, abbeys, gardens, zoos, theme parks and other visitor attractions whose mapped point lies inside the commune of Osmoy, then those in the communes within 5 km of its centre, and well-known places within 40 km. Houses, ruins and gardens need a sign they’re open to visitors; places marked private, closed or disused are left out. The historic-monument link is the Culture ministry’s Mérimée record. A place that isn’t mapped isn’t listed, so this isn’t everything there is to see.
Sources: OpenStreetMap (© OpenStreetMap contributors, ODbL), Wikidata (CC0: descriptions, websites, Wikipedia articles), the Culture ministry’s Mérimée database (Licence Ouverte 2.0), IGN commune boundaries. Distances are from the commune’s centre point.
Photos from Wikimedia Commons, each under its own licence (our copy, resized).
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.