The metamorphic basement of the Algyő–Ferencszállás–Kiszombor area, located in the SE part of the Pannonian Basin, consists of crystalline highs covered by thick Neogene sediments. Although productive hydrocarbon reservoirs are typically found in these Neogene formations, the crystalline basement may also play a role in fluid storage and migration. However, its structure and reservoir potential remain poorly understood. This comprehensive petrological study shows that the area comprises distinct blocks with different metamorphic evolutions. The area mainly consists of gneiss varieties, genetically related through their metamorphic histories. The first regional amphibolite facies metamorphism (M1) of gneiss terrains was overprinted by a contact metamorphic (metasomatic) effect (M2) at varying crustal depths. The peak conditions of M1 in the garnet–biotite gneiss reached ~9.5–10.5 kbar and ~670–720 °C, followed by M2 overprint at T_max~570–630 °C. In the garnet–kyanite gneiss, M1 reached ~7.5–8.5 kbar and ~600–650 °C, with M2 at T_max~730 °C. In the pseudomorph-bearing gneiss, M1 peak conditions were ~6.5–7.0 kbar and ~550–580 °C, overprinted by a contact effect in the andalusite stability field. Earlier geochronological data suggest the M1 metamorphism is of Variscan age, while M2 event likely related to an Alpine, magmatic event. These gneiss terrains form neighbouring basement blocks, with proposed post-metamorphic structural boundaries. In the Ferencszállás area, a metagranite body represents an intrusion in these gneiss terrains, which may have been the source of the contact overprint. In the shallowest structural positions, low-grade greenschist facies chlorite schist (T_max~270–300 °C) and epidote orthogneiss occur, separated by post-tectonic structural boundaries. Considering the hydrodynamic behaviour of other buried hill reservoirs in the Pannonian Basin, the brittle structural boundaries between blocks may serve as hydrocarbon migration pathways from the adjacent over pressured sub-basins (Szeged Basin, Makó Trough) or act as fluid reservoirs.