Milecastle 68 (Boomby Gill) is a conjectured milecastle of the Roman Hadrian’s Wall. The location of the mile fort could only be determined by measuring the distance to the neighboring fortifications of Hadrian’s Wall. So far, however, no remains of the fort have been discovered. In 1969 employees of the English Heritage carried out a first field inspection. Remnants of the mile fort could not be found. In 1972, employees of the English Heritage investigated an old exploratory trench there, it was probably dug to uncover the northwest corner of the mile fort, but these efforts were unsuccessful. There were many loose stones in the trench, some of them very large. In 1990 a field inspection was carried out again as part of the Hadrian’s Wall project. Visible remains could not be observed, and there was no trace of the exploratory trench either.