Milecastle 43 lies beneath the north wall of Great Chesters Fort
Milecastle 43 was situated at Great Chesters, and was destroyed when the Aesica fort was built.
The foundations were discovered during an excavation in 1939, and were found beneath the fort wall and rampart between the north gate and north-west angle of Aesica. The excavations showed that the milecastle had a short axis with a Type I gateway. There are no visible remains.
Each milecastle on Hadrian's Wall had two associated turret structures. These turrets were positioned approximately one-third and two-thirds of a Roman mile to the west of the Milecastle, and would probably have been manned by part of the milecastle's garrison. The turrets associated with Milecastle 43 are known as Turret 43A and Turret 43B.
The Hadrian's Wall Path passes through the remains of Aesica fort close to the location of the milecastle. The sites of both turrets are accessible via the Hadrian's Wall Path.