Just before 4 a.m. on January 25th, 1799 a large historical earthquake affected the coastal Vendée and the Nantes area, devastating Bouin (Publicateur de Nantes, 1 Ventose an VII, Limasset et al. 1992). Despite several historical informations, the seismogenic sources potentially responsible for this event remain marginally documented. Here we present a focused multidisciplinary study in the epicentral area of the 1799 earthquake aiming at the identification of faults potentially responsible for this event. We combined outcomes from marine geophysics (seismic reflexion, HR bathymetry), onshore drilling data, gravity modelization, morphometric analysis and a temporary seismological experiment.