I. For several decades, the etymology of Oppenans (Haute-Saône) has given rise to interpretations that are less and less controlled and less and less credible. It is time to put an end to this drift by returning to the solution given by Gamillscheg in 1936 (a solution totally ignored by French toponymists): namely, a Burgundian deanthroponymic derivative *Uppa.n‑ingôs. The integration of this place-name into Ostic morphology (flexion and derivation) and anthroponymy, as well as its inclusion in a tight group of *‑ingôs formations, make this solution, which is also phonetically regular, as reliable as possible. The creation of *Uppaningôs must therefore be placed between 457 and 534, the extreme dates of Burgundian political domination over the city of the Sequans. — II. It is proposed that En Népouley, the name of an area split between the communes of Oppenans and Borey, is a Latin collective derivative *nespol-etu ‘place where medlar trees grow’. The base of this derivative does not have the oilic syncopation, but a suffixal graft into *-ọ́la, which shifted the accent. This process is well documented in Franco-Provençal (south), in the Vivaro-Alpine amphizone and in Occitan. Furthermore, the topographical and toponymic contexts suggest that *nespoletu is a typical saltus name predating the establishment of the finage of the villa of *Uppaningôs/Oppenans between 457 and 534. It follows that the Népouley treatment provides a clue to the approximate date at which what is now the oilicFranche-Comté area first became part of the emerging Franco-Provençal domain.