Unlike de Burgh's nearby star fort, which was primarily earthwork and demolished in the 1830s, Corneille's bastion fort was built of brick and limestone.

The main body of the fort is approximately 2 acres in area and is surrounded by a dry moat.
Each corner is defended by a demi-bastion (with embrasures), and the walls are approximately 1.5 metres (5 ft) thick.
The large barrel-vaulted brick magazine chambers themselves are approximately 270 square metres (2,900 sq ft) in size and located to the north-west of the main enclosure.
These were serviced by overhead cranes and gantries – for moving powder kegs.
A later triangular barracks and accommodation block was added on the south-side in 1801, to designs by Francis Johnston.
Other sheds and outbuildings were added in the 20th century.
Unlike de Burgh's nearby star fort, which was primarily earthwork and demolished in the 1830s, Corneille's bastion fort was built of brick and limestone.
The main body of the fort is approximately 2 acres in area and is surrounded by a dry moat. Each corner is defended by a demi-bastion (with embrasures), and the walls are approximately 1.5 metres (5 ft) thick. The large barrel-vaulted brick magazine chambers themselves are approximately 270 square metres (2,900 sq ft) in size and located to the north-west of the main enclosure. These were serviced by overhead cranes and gantries – for moving powder kegs. A later triangular barracks and accommodation block was added on the south-side in 1801, to designs by Francis Johnston. Other sheds and outbuildings were added in the 20th century.
Magazine Fort