Hadrian’s Wall – Milecastle 21 – Halton Shields
Roman Mile Castle in Newcastle upon Tyne
Milecastle 21 (Down Hill) was a milecastle of the Roman Hadrian’s Wall. The site was identified by measurement only, as the milecastle’s remains have been totally removed. This is probably due to extensive quarrying at the site, which now lies under pasture (and partly beneath the Military Road).