Positioned at the head of one of the main routes in and out of the Scottish Highlands, it was occupied by Legion XX Valeria Victrix and covered a total area of 21.5 hectares (53 acres).

[1] Construction of the large fortress would have taken two or three seasons and a temporary camp was built nearby to house and protect the soldiers over the winter.

[2] Unlike other legionary fortresses in Britain, Inchtuthil was not later built over and its layout was still largely preserved when Sir Ian Richmond excavated it between 1952 and 1965.

Its defences consisted of a turf rampart faced with stone, with an outside ditch and gatehouses on each side, following the standard Roman plan.

[citation needed] During the excavations started by Richmond in the 1950s, a large pit was found in the summer of 1960 containing 875,400 complete iron nails (Square shaft) ranging from 50–410 mm (2–16 in) plus another 28 (round shaft nails) weighing 7 short tons (6.4 t), together with other iron objects, including cartwheel rims weighing a combined total weight of ten tonnes.