Milecastle 42 can be found on one of the best preserved sections of Hadrian's Wall. It is situated on a steep south facing slope, 10 metres south of Cawfield Crags, and looks over Hole Gap to the west. The remains measure 17.8 metres east-west by 14.4 metres north-south internally, with walls 2.8 metres thick and 1.4 metres high. 

When the milecastle was excavated in 1847-8 part of a dedication slab indicating that the milecastle had been built by the Legio II Augusta was discovered. It was excavated again in 1936 and these excavations showed that the milecastle had a short axis, with a Type I gateway. 

The remains are accessible from the Hadrian's Wall Path and Cawfields Picnic Area car park is not far away if youre visiting in the car. Check out our Hadrian's Wall app for more information on whats close by to each milecastle and learn a little more about Hadrian's Wall Country.