Small topographic depressions can provide information on past and present groundwater recharge processes. The Landes Triangle (SW France) is dotted with more than 2,400 of them, valued for their ecological significance. Yet, their origin and hydrogeological implications remain poorly understood. This paper aims to elucidate their formation process, with special emphasis on the Villagrains-Landiras (VL) anticline sector: a key recharge zone for regional aquifers, which also features the highest density of depressions. We first assess the likelihood of three historical hypotheses with open GIS data, then detail the near-surface structure of a depression in the VL sector with electrical resistivity tomographies and ground penetrating radar. We identify two distinct groups of depressions in terms of morphology, distribution and geological context (SE1 and SE2). SE2 shows characteristics consistent with aeolian origin. SE1 includes 97% of the VL anticline depressions, and exhibits circular morphology and proximity to karst features, natural streams, faults, and neighboring depressions, suggesting a karst origin. However, 18% of SE1 may rather be of periglacial origin, as they do not lie in the crypto-karst area derived from GIS references. Yet, the geophysical survey specifically designed to target periglacial features in this context showed only evidence of subsidence, and none of cryogenic sediment or solifluction. We conclude that a karst origin remains the best hypothesis in the VL anticline area, and highlight that sole reliance on GIS references may underestimate crypto-karst extent. Further geological investigation is therefore needed to fully capture its extent near the VL anticline, and map related water pathways.< Réduire