Inchtuthill "The Redoubt"
Apparently a walled stores facility associated with the adjoining fort. The area is located in the northeast corner of the fort plateau, about 122 m east of the legionary fortress.
The erosion of the embankment has over time destroyed all traces of the earthworks to the southeast, but excavations (Richmond, St. Joseph) in 1965 indicated that this side was probably just a simple earthworks.
The south, west and north sides followed the slope that favoured a defence. From the only gate on the northwest side, which was strangely placed near the western corner, one reached a road leading to the southeast, the shortest connection to the southeast gate of the legionary fortress. The south side runs parallel to the street leading from the Porta Principalis Sinistra(East gate) led to the river. It is believed that the fortification was originally built to protect this road. It is possible that supplies were also stored there during the construction period. A third possible explanation would be that the fortress demolition teams camped there. It took up an area of 1.65 hectares, including the wall. Of the three sides that have been preserved, two are oriented at right angles. The upstream V-shaped weir ditch was 3–5 m wide and 1–2 m deep. The countercarpwas thrown out of the excavated material and was up to 7.3 m wide. The base of the earth wall was 6.1 m wide. On the north side it was still up to a height of 1.53 m, while it was only 0.76 m high in the west. In the south it was already badly eroded. The excavations from 1964 to 1965 confirmed that the wall also consisted of excavated material from the trench. The V-profile of all the trenches was very distinct, but their bottom was square in the western and southern sections. A single gate in this position gave access to the road that led to the east gate. It consisted of a passage with a width of 4.27 m and two post holes on each side, no traces of a tower or even a guardroom were to be seen. Only a trench (1.22 m wide) could be observed there, it probably came from pre-Roman times. During the investigations within the defence system, which were severely obstructed by the trees, no traces of buildings could be found, individual graves indicate the erection of tents. Only some Flavian ceramic fragments could be recovered, they allowed the dating of the Redoupt as undoubtedly Roman. In particular, the lack of permanent buildings indicates that the occupation was only temporary. In addition to the legionary camp, eight more cohort forts were probably under construction, for which Inchtuthil was intended as a supply base. This could be an indication of what the redoubt was used for. The supplies could have been brought by sea and the Tay at least as far as the Perth area, even if the fort in Bertha could no longer be reached in this way. Irrespective of the exact position of the transhipment point, the onward transport would then have taken place by land to Inchtuthil. It would be the logical place for a central replenishment depot to quickly supply the forts under construction with the necessary material from there, at least for those to the northeast of it. The area of the Redoubt would have provided enough storage space for it.