Abbaye de Saint-Rambert-en-Bugey
Abbey located in Ain, in France.
Each edition grades its towns against each other only.

3 of the 5 places to visit in and around Oncieu are châteaux or heritage sites. All of them lie outside Oncieu. Beyond the town, the best known is Abbaye royale d’Hautecombe, 36 km off.
After Abbaye de Saint-Rambert-en-Bugey, look out for 2 châteaux, a museum and a gallery.
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 map shows most of the 5 nearby to the southwest.
The first 20 on the list, numbered as below. The shape is the commune of Oncieu; the orange dot is its centre. © OpenStreetMap contributors · commune boundary: IGN
Most are châteaux or heritage sites, 3 in all, ahead of museums or galleries (2).
Dark: in Oncieu. Light: in the communes within 5 km of its centre.
Its 5 places all lie within 5 km of its centre.
Nothing is mapped in Oncieu itself; these are within 5 km of its centre.
The standout of the 12 is Abbaye royale d’Hautecombe, 36 km from town.
MuseumChâteau des Allymes5.1 km west, in Ambérieu-en-BugeyAttractionAttractionCascade de Glandieu35 km south, in Brégnier-Cordon
Monastery or conventMonastère royal de Brou32 km northwest, in Bourg-en-BresseCathedralCathedralCathédrale Saint-Jean de Belley28 km southeast, in BelleyChâteauChâteauChâteau de Varey9.1 km northwest, in Saint-Jean-le-VieuxAttractionAttractionBarrage de Génissiat28 km east, in FranclensAttractionAttractionAbbaye Notre-Dame d'Ambronay10 km northwest, in AmbronayCathedralCathedralCocathédrale Notre-Dame-de-l'Annonciation de Bourg-en-Bresse33 km northwest, in Bourg-en-Bresse
ZooParc des oiseaux34 km west, in Villars-les-DombesChâteauChâteauChâteau de Poncin15 km north, in PoncinAbbeyAbbeyAbbaye Notre-Dame-des-Dombes30 km west, in Le PlantayPlaces within 40 km of Oncieu with an article in both French and English Wikipedia, nearest first.
Nothing is mapped in Oncieu itself, but within 5 km there are Abbaye de Saint-Rambert-en-Bugey, Château de Cornillon, Musée des traditions bugistes and Château de Luisandre.
2 museums and galleries in town or within 5 km, including Musée des traditions bugistes and Galerie d'art du Quai.
The nearest with articles in both French and English Wikipedia: Abbaye royale d’Hautecombe (36 km), Château des Allymes (5.1 km), Cascade de Glandieu (35 km), Monastère royal de Brou (32 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 Oncieu, 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.