| Ondefontaine | |
| Arrondissement: | Vire |
| Canton: | Les Monts d'Aunay |
| Insee: | 14477 |
| Postal Code: | 14260 |
| Commune: | Les Monts d'Aunay |
| Coordinates: | 48.9969°N -0.6831°W |
| Elevation M: | 311 |
| Elevation Min M: | 205 |
| Elevation Max M: | 325 |
| Area Km2: | 15.26 |
| Population: | 320 |
| Population Date: | 2019 |
| Population Footnotes: | [1] |
Ondefontaine (pronounced as /fr/) is a former commune in the Calvados department in the Normandy region in northwestern France. On 1 January 2017, it was merged into the new commune Les Monts d'Aunay.[2]