Inner Bailey Keep

The Inner Bailey Keep of Carlisle Castle is an important historical structure dating from the early 12th century, with alterations made in the mid-16th century and the 19th century. The keep features extremely thick walls made of squared red sandstone, which include a stepped chamfered plinth, broad pilasters, and splayed embrasures at the parapets. It has a flat lead roof and stands four storeys high, with a roughly square shape.

The east face of the keep has an off-centre doorway that is recessed for a portcullis. There is an additional entrance at first floor level on the left, which has been covered by a two-storey forebuilding that is partly medieval but has undergone significant alterations; a replica panel from 1577 is built into one wall. The keep has various original slit windows, some of which have been enlarged to accommodate casements or sashes with glazing bars. One window features the inscription "JOHN HYDE 1714."

On the north face, there is a sloping gun ramp that has been modified to a stepped form, while earthen ramparts cover parts of the west and south faces. The broad splayed embrasures at the parapets are believed to be a 16th-century alteration that reduced part of the original height of the keep.

Inside, the keep retains many original and later features, including a vaulted basement, a 12th-century fireplace, and mural chambers with 15th-century carvings. The listing also includes the former 1827 Quartermaster's store that adjoins the forebuilding, as well as the remaining rear wall of the 1577 Governor's House, which is adjacent to the keep.