Knag Burn Gateway is one of the few gates through the wall that isn't part of a
milecastle or
fort. The remains indicate that the structure consisted of a single-lane gateway, with guard-chambers on either side and a gate at each end, thus allowing two-stage controlled passage through the wall. Professor
I. A. Richmond suggested that the gateway was constructed to allow trade traffic through the wall some time in or after the fourth century. The gateway was discovered in 1855 and excavated in 1936 and 1988. The structure consists of the wide gateway with two small structures either side. The two cell structures at either side of the gateway measure by , with entrances wide (on the side nearest the gateway), which open onto a passage. ==Monument record==