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.
It is therefore notable as the site which provides the only complete plan of a legionary fortress anywhere in the Roman empire.

Its defences consisted of a turf rampart faced with stone, with an outside ditch and gatehouses on each side, following the standard Roman plan.
The legion it accommodated would have numbered 5,400 at full strength, though there would have been additional specialist troops accompanying them.

Facilities included a hospital (valetudinarium) that covered 5,000 square metres, a workshop covering 3,500 square metres and 64 barrack buildings.
The timber walls of these buildings have been calculated to have had a total perimeter of seven miles (10 km).
A headquarters building containing an aedes where the legion's colours and images of the emperor would have been kept has also been identified in the insula in the centre of the fortress.
However, it was much smaller than would be expected for a legionary fortress, and must have been of a temporary nature.
The large empty insula to its east should have been the site for the Praetorium, the commander's house.
However, no signs of building foundations for such a large structure were found though the site had been levelled and prepared.

Inchtuthil was only briefly occupied and was evacuated around summer AD 86 and certainly no later than early in AD 87.
The reason for this was probably that Legio II Adiutrix had been called to Moesia from its base in Deva Victrix (Chester) to deal with a Dacian invasion in 86 and XX Valeria Victrix was obliged to move back south to take its place.
However recent archaeology has cast some doubt on this, indicating that the fortress may have been in use for considerably longer than previously thought.
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. It is therefore notable as the site which provides the only complete plan of a legionary fortress anywhere in the Roman empire. 
Its defences consisted of a turf rampart faced with stone, with an outside ditch and gatehouses on each side, following the standard Roman plan. The legion it accommodated would have numbered 5,400 at full strength, though there would have been additional specialist troops accompanying them.
Facilities included a hospital (valetudinarium) that covered 5,000 square metres, a workshop covering 3,500 square metres and 64 barrack buildings. The timber walls of these buildings have been calculated to have had a total perimeter of seven miles (10 km). A headquarters building containing an aedes where the legion's colours and images of the emperor would have been kept has also been identified in the insula in the centre of the fortress. However, it was much smaller than would be expected for a legionary fortress, and must have been of a temporary nature. The large empty insula to its east should have been the site for the Praetorium, the commander's house. However, no signs of building foundations for such a large structure were found though the site had been levelled and prepared.
Inchtuthil was only briefly occupied and was evacuated around summer AD 86 and certainly no later than early in AD 87. The reason for this was probably that Legio II Adiutrix had been called to Moesia from its base in Deva Victrix (Chester) to deal with a Dacian invasion in 86 and XX Valeria Victrix was obliged to move back south to take its place. However recent archaeology has cast some doubt on this, indicating that the fortress may have been in use for considerably longer than previously thought.
Inchtuthil