The castle, recorded as 'Kragane' in 1574 when it belonged to Walter Mcffregha, remained inhabited well into the 18th century, though by then it had undergone significant modernisation. This three-storey tower house, which stood unroofed when surveyed in the early 20th century, reveals layers of history through its surviving features and alterations.

The castle's original defensive architecture is still evident in its structure. A distinctive base-batter rises approximately 2.7 metres, whilst the main entrance on the eastern wall features a rebated pointed arch leading into a small lobby. From here, doorways branch off to a spiral staircase tucked into the southern corner, the main ground-floor chamber to the west, and a guardroom to the north with its square-headed doorway. The upper floors, accessed via the spiral stairs, contained both subsidiary chambers and main rooms, with a vault separating the first and second floors. Original ogee-headed windows survive in various walls, some featuring decorative spandrels, whilst larger openings on the third floor likely housed mullioned windows. The presence of fireplaces on multiple floors, including a modernised example in the western wall, speaks to the comfort sought by later occupants.

By the mid-20th century, the castle showed significant deterioration; a 1944 survey found only fragments of the spiral staircase remaining and the floors of the subsidiary chambers lost. The building served various purposes over time, with the ground floor being used as a store and byre in 1956. However, Cregganna Castle's story took a positive turn when, during a 1983 survey, it was found to be fully restored and occupied once again, bringing this remarkable tower house full circle from medieval stronghold to modern dwelling.