Constructed between the second half of the 4th century and beginning of the 5th century. They belong to the period of the Roman Empire during which the catacombs were rare, which does that those of Montalbán is only in Spain. Nevertheless, it is possible to state small investigation executed in the zone, they're not being known the existence of any more remains of value in Tentecarreta's places (as for example, the location of the settlement from which the above-mentioned catacomb originated).
It has discovered two galleries arranged in a cross and orientated according to the cardinal points. They are extremely narrow and tortuous, with a condition of conservation very eroded by the high dampness and the avalanches of mud. Nevertheless, in some zones of the ceiling there stay spots of the enlucido that it was covering his walls, probably polychrome. Equally, there appear between the mud small rectangular and rhomboid bricks, surely used since it would occur. The gallery South shelters a collective burial and, to beginnings of the gallery East. A niche exists where an individual was lying in foetal position; in both one has found funeral apparel.
The only valuable element from the exterior is an artesian well, which departs from one of the galleries, produced by the alterations of the groundwater level. The tangible heritage constituted by the underground galleries discovered up to the current importance, they suppose for the population of Montalbán an unequivocal testimony of his more remote past. Due to this, the zone has turned into an element of ethnological interest for the municipality.
In 2009, there was realized an expedition in which they took information, there rejected possible obstructed galleries and topografió the deposit. At present, this space is not accessible.