46. How big were the forts on Hadrian’s Wall?

The Wall forts ranged in size between 1.35ha (3.3 acres) and 3.7ha (9.3 acres) according to the unit they were designed to accommodate. The smallest Hadrianic forts (Great Chesters and Castlesteads) were probably intended for quingenary (500-strong) infantry units, the largest (Stanwix) for a milliary (1,000-strong) cavalry unit, but the other sizes overlapped for milliary infantry and quingenary cavalry and mixed units.

Further reading: Breeze and Dobson 2000